Optical element holding device

ABSTRACT

An optical element holding apparatus ( 39 ) provided with a holding portion ( 43 ) for holding a flange portion ( 38   a ) of an optical element ( 38 ). The holding portion includes a bearing surface block ( 50   a ) having a bearing surface ( 49 ), which contacts the flange portion, and a bearing surface block support mechanism ( 51 ), which rotatably supports the bearing surface block about a tangential axis (Y) of the optical element. This structure holds the optical element ( 38 ) with the optical element holding apparatus ( 39 ) in a kinematical manner and maintains satisfactory imaging performance in the optical element.

TECHNICAL FIELD

[0001] The present invention relates to an optical element holdingapparatus for holding an optical element, and, more particularly, to anoptical element holding apparatus for a projection optical system of anexposure apparatus which is used in a photolithography step performedduring a process for fabricating micro devices, such as a semiconductordevice, a liquid crystal display device, an imaging device, or anthin-film magnetic head, or in a process for forming masks, such asreticles and photomasks.

BACKGROUND ART

[0002] As shown in FIGS. 1 and 2, a conventional optical element holdingapparatus 200 has a ring-like frame 202, which houses an optical element201, such as a lens. Three bearing surfaces 204, which support theoptical element 201, are arranged on the inner wall of the frame 202 atequiangular distances. Screw holes 205 are formed in the top surface ofthe frame 202 at positions corresponding to the bearing surfaces 204.Bolts 207 are fastened into the three screw holes 205 by means of threerespective clamp members 206.

[0003] The fastening of the bolts 207 clamps a peripheral flange 201a ofthe optical element 201 between the clamp members 206 and the bearingsurfaces 204. This holds the optical element 201 in the frame 202 at apredetermined position. Even when force is applied to the opticalelement 201 in a direction intersecting the optical axis of the opticalelement 201, the clamp members 206 prevent the optical element 201 frombeing displaced and stably hold the optical element 201.

[0004] Due to the miniaturization of semiconductor device patterns, aprojection optical system of, for example, an exposure apparatus used tofabricate semiconductor devices is required to have higher resolution.To acquire higher resolution, it is important that the optical element201 be fixed when maintaining the optical performance of the opticalelement 201 of the projection optical system. That is, to maintain theoptical performance of the optical element 201, changes in the surfaceaccuracy of the optical surface of the optical element 201 must beminimized when the optical element 201 is supported in the lens barrelof the exposure apparatus.

[0005] The optical element 201 is placed on the three bearing surfaces204 and is clamped by the clamp members 206. The surface shape of theclamped optical element 201 is affected significantly by the machiningaccuracy of the bearing surfaces 204 (the positional relationship of thebearing surfaces 204), the clamp members 206, and the peripheral flange201 a of the optical element 201. In other words, machining must beperformed with extremely high accuracy to make the bearing surfaces 204identical and arrange the bearing surfaces 204 in the vicinity of theideal positions so that such affect becomes subtle enough to benegligible. In addition to the bearing surfaces 204, the clamp members206 and the peripheral flange 201a must also be machined with extremelyhigh accuracy. This makes the machining of the individual members verytroublesome and increases manufacturing costs.

[0006] Even if the bearing surfaces 204, the clamp members 206, and theperipheral flange 201 a were machined with extremely high accuracy, theframe 202 may slightly be distorted when the frame 202 clamping theoptical element 201 is fitted in the lens barrel. Such distortionslightly changes the positional relationship of the bearing surfaces 204and distorts the optical surface of the optical element 201. This lowersthe optical performance of the optical element 201.

[0007] Further, the pattern miniaturization requires a projectionoptical system, which has extremely low wave front aberration anddistortion. To meet such requirement, the optical axis of the opticalelement 201 must be aligned as accurately as possible in the projectionoptical system.

[0008] To accurately position the optical element 201 and align theoptical axis of the optical element 201, an outer surface 202 a and abottom surface 202 b of the frame 202 are connected with an inner walland receiving portion of the lens barrel. Thus, there is subtle freedomwhen the frame 202 is attached to the lens barrel. It is thereforenecessary to attach the frame 202 to the lens barrel with meticulouscare. This is troublesome.

[0009] Furthermore, if the frame 202 is inserted in the lens barrel in aslightly tilted state and fitted to the lens barrel with excessive loadapplied to the frame 202, the frame 202 may be distorted. The distortionof the frame 202 produces an unpredictable stress on the optical element201, thus lowering the accuracy of the optical surface of the opticalelement 201.

DISCLOSURE OF THE INVENTION

[0010] It is a primary object of the present invention to provide anoptical element holding apparatus that maintains the optical performanceof an optical element in a satisfactory manner.

[0011] It is a secondary object of the present invention to provide anoptical element holding apparatus that positions an optical element in afacilitated manner with high accuracy.

[0012] The present invention provides an optical element holdingapparatus provided with a holding portion for holding a peripheralportion of an optical element. The holding portion includes a bearingsurface block having a bearing surface, which contacts the peripheralportion of the optical element, and a bearing surface block supportmechanism for rotatably supporting the bearing surface block about atangential axis of the optical element.

[0013] The present invention provides an optical element holdingapparatus, which includes a holding portion for holding a peripheralportion of an optical element and a fastening portion to which theholding portion is fastened. The holding portion includes a bearingsurface block having a bearing surface that contacts the peripheralportion of the optical element, a base portion fixed to the fasteningportion, and a pair of link mechanisms for restricting movements of thebearing surface block relative to the base portion in a plurality ofdifferent directions and for connecting the base portion and the bearingsurface block rotatably about each axis of the plurality of differentdirections.

[0014] The present invention provides a holding apparatus including aholding portion for holding a member to be held. The holding portionincludes a drive mechanism for providing the member to be held withthree movements along three coordinate axes with an origin beingsubstantially the center of the member to be held and two rotationsabout at least two coordinate axes of the three coordinate axes.

[0015] The present invention provides an optical element holdingapparatus including a holding member for holding a peripheral portion ofan optical element, three flexure members for holding the holding memberat three locations, and first and second manipulation members connectedto at least one of the flexure members for manipulating the at least oneflexure member. The manipulation member is held such that manipulationof the first manipulation member causes the at least one flexure memberto move the optical element in a first direction and such thatmanipulation of the second manipulation member causes the at least oneflexure member to move the optical element in a second direction thatdiffers from the first direction.

BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The invention, together with objects and advantages thereof, maybest be understood by reference to the following description of thepresently preferred embodiments together with the accompanying drawingsin which:

[0017]FIG. 1 is a cross-sectional view of a conventional optical elementholding apparatus;

[0018]FIG. 2 is an exploded perspective view of the optical elementholding apparatus in FIG. 1;

[0019]FIG. 3 is a schematic structural diagram of an exposure apparatus;

[0020]FIG. 4 is a perspective view of an optical element holdingapparatus according to a first embodiment of the present invention;

[0021]FIG. 5 is a perspective view of the optical element holdingapparatus in FIG. 4 as seen from another angle;

[0022]FIG. 6 is a perspective view of a holder of the optical elementholding apparatus in FIG. 4;

[0023]FIG. 7 is a perspective view of a base member of the holder inFIG. 6;

[0024]FIG. 8 is a front view of the base member in FIG. 7;

[0025]FIG. 9 is a cross-sectional view taken along line 9-9 in FIG. 8;

[0026]FIG. 10 is a perspective view of a clamp member of the holder inFIG. 6;

[0027]FIG. 11 is a perspective view of the clamp member of the holder inFIG. 6 as seen from another angle;

[0028]FIG. 12 is a cross-sectional view taken along line 12-12 in FIG.11;

[0029]FIG. 13 is a bottom view of a pad member of the holder in FIG. 6;

[0030]FIG. 14 is a cross-sectional view taken along line 14-14 in FIG.13;

[0031]FIG. 15 is an enlarged plan view of the holder in FIG. 6;

[0032]FIG. 16 is a cross-sectional view taken along line 16-16 in FIG.15;

[0033]FIG. 17 is a cross-sectional view taken along line 17-17 in FIG.15;

[0034]FIG. 18 is an enlarged plan view of a weight support mechanism ofthe optical element holding apparatus in FIG. 4;

[0035]FIG. 19 is a schematic diagram of the holder in FIG. 6;

[0036]FIG. 20 is an enlarged bottom view showing a pad member in anoptical element holding apparatus according to a second embodiment;

[0037]FIG. 21 is a cross-sectional view taken along line 21-21 in FIG.20;

[0038]FIG. 22 is an enlarged perspective view showing a base member inthe optical element holding apparatus according to the secondembodiment;

[0039]FIG. 23 is a perspective view of an optical element holdingapparatus according to a third embodiment of the invention;

[0040]FIG. 24 is a plan view of the optical element holding apparatus inFIG. 23;

[0041]FIG. 25 is a side view of the optical element holding apparatus inFIG. 23;

[0042]FIG. 26 is a cross-sectional view taken along line 2626 in FIG.23;

[0043]FIG. 27 is a partial, enlarged perspective view showing a lenschamber and a holder of the optical element holding apparatus in FIG.23;

[0044]FIG. 28 is a perspective view of a frame of the optical elementholding apparatus in FIG. 23;

[0045]FIG. 29 is a partial, enlarged plan view of the frame of theoptical element holding apparatus in FIG. 23;

[0046]FIG. 30 is a partial, enlarged side view of the frame of theoptical element holding apparatus in FIG. 23;

[0047]FIG. 31 is a partial, enlarged side view of a flexure body of theoptical element holding apparatus in FIG. 23;

[0048]FIG. 32 is a cross-sectional view taken along line 32-32 in FIG.29;

[0049]FIG. 33 is a cross-sectional view taken along line 33-33 in FIG.29;

[0050]FIG. 34 is a perspective view showing the optical element holdingapparatuses in FIG. 23 in a superimposed state;

[0051]FIG. 35 is an exemplary diagram of the optical element holdingapparatus in FIG. 23;

[0052]FIG. 36 is a schematic diagram of the optical element holdingapparatus in FIG. 23;

[0053]FIG. 37 is a diagram explaining parallel movement of an opticalelement;

[0054]FIG. 38 is a perspective view showing a lens chamber and a basemember of the optical element holding apparatus in FIG. 23;

[0055]FIG. 39 is a perspective view of the frame and the flexure body ofthe optical element holding apparatus in FIG. 23;

[0056]FIG. 40 is a schematic diagram of an optical element holdingapparatus according to a fourth embodiment of the present invention;

[0057]FIG. 41 is a cross-sectional view showing a rigid body of FIG. 40;

[0058]FIG. 42 is a cross-sectional view taken along line 42-42 in FIG.41;

[0059]FIG. 43 is a schematic diagram of an optical element holdingapparatus according to a fifth embodiment of the present invention;

[0060]FIG. 44 is a schematic diagram of an optical element holdingapparatus according to a sixth embodiment of the present invention;

[0061]FIG. 45 is a schematic diagram of an optical element holdingapparatus according to a seventh embodiment of the present invention;

[0062]FIG. 46 is a cross-sectional view showing a rigid body of FIG. 45;

[0063]FIG. 47 is a cross-sectional view taken along line 47-47 in FIG.46;

[0064]FIG. 48 is a flowchart illustrating an example of a semiconductordevice fabrication process; and

[0065]FIG. 49 is a flowchart illustrating a substrate processing in thesemiconductor device fabrication process.

BEST MODE FOR CARRYING OUT THE INVENTION

[0066] (First Embodiment)

[0067] An optical element holding apparatus 39 according to a firstembodiment of the present invention will now be described with referenceto FIGS. 3 through 19. Referring to FIG. 3, the optical element holdingapparatus 39 is used to hold a lens 38 of a projection optical system 35of an exposure apparatus 31 that is used in the fabrication ofsemiconductor devices.

[0068] As shown in FIG. 3, the exposure apparatus 31 includes a lightsource 32, an illumination optical system 33, a reticle stage 34, whichholds a reticle R functioning as a mask, a projection optical system 35,and a wafer stage 36, which holds a wafer W functioning as a substrate.

[0069] The light source 32 emits, for example, an ArF excimer laser beamhaving a wavelength of, for example, 193nm. The illumination opticalsystem 33 various lens systems, for example, an optical integrator, suchas a fly-eye lens or a rod lens, a relay lens, and a condenser lens, andan aperture stop, which are not shown in the drawings. The illuminationoptical system 33 adjusts the exposure light EL emitted from the lightsource 32 to light that uniformly illuminates a pattern on the reticleR.

[0070] The reticle stage 34 is arranged such that the surface on whichthe reticle R is mounted is substantially perpendicular to the directionof the optical axis of the projection optical system 35 on the outgoingside of the illumination optical system 33 (the incoming side of theexposure light EL in the projection optical system 35). The projectionoptical system 35 includes a lens barrel 37 including a plurality oflens barrel modules 420 in each of which the lens 38 is held in agenerally horizontal state by the optical element holding apparatus 39.

[0071] The wafer stage 36 is located on the exposure light EL outgoingside of the projection optical system 35. The wafer mounting surface ofthe wafer stage 36 is arranged to intersect the optical axis directionof the projection optical system 35. When the exposure light EL passesthrough the projection optical system 35, the image of the pattern onthe reticle R is reduced by a predetermined reduction magnification. Thereduced image of the pattern is then transferring onto the wafer W onthe wafer stage 36.

[0072] The details of the optical element holding apparatus 39 will bedescribed below.

[0073]FIG. 4 is a partial, cutaway, exploded perspective view of theoptical element holding apparatus 39, FIG. 5 is a perspective view ofthe optical element holding apparatus 39 in FIG. 4 as seen from below,and FIG. 6 is a partial, enlarged perspective view of the opticalelement holding apparatus 39.

[0074] The optical element 38 is formed of a glass material, such assynthesized quartz, which has a relatively large fracture strength. Theoptical element 38 has a flange portion 38 a (see FIG. 6) defined at itsperipheral portion. The optical element holding apparatus 39 includes alens frame 42, which serves as the lens barrel module 420 that functionsas an external unit, and three holders 43, which are disposed at anequiangular distance on the lens frame 42 and hold the flange portion 38a of the optical element 38. Each holder 43 includes a base member 45and a clamp member 46. The lens frame 42 is formed of metal, such asaluminum, in a ring-like shape. Attachment grooves 44 for attachment ofthe clamp members 46 are formed on the surface of the lens frame 42 atequiangular distances. Recesses 60 (see FIG. 6) for receiving bearingsurface blocks of the base members 45 are formed on the inner surface ofthe lens frame 42 at positions corresponding to the attachment grooves44. The recesses 60 prevent enlarging of the diameter of the lens frame42.

[0075] In the attachment groove 44, the clamp member 46 is attached tothe lens frame 42 by a pair of bolts 68. At this time, the heads of thepair of bolts 68 do not protrude from the surface of the lens frame 42.When the surface of one lens frame 42 comes into contact with the bottomsurface of another lens frame 42, therefore, the bottom surface of theanother lens frame 42 does not contact the bolts 68. A spacer isarranged between the top surface of one lens frame 42 and the bottomsurface of another lens frame 42 to adjust the space between the frames42. This determines the position of the optical element, which is heldby each lens frame 42, with respect to the optical axis direction. Thus,the optical element does not contact the bottom surface of the upperlens frame 42 even if the optical element slightly projects from the topsurface of the lower lens frame 42 as long as the optical element isthinner than the spacer. The base member 45 is secured to the bottomsurface of the lens frame 42 by a pair of bolts (see FIG. 5).

[0076] Next, the holder 43 will be described. First, the base member 45will be discussed. FIG. 7 is an enlarged perspective view of the basemember 45, FIG. 8 is a front view of the base member 45, and FIG. 9 is across-sectional view of the base member 45 taken along line 10-10 inFIG. 8. Through holes 52 for a pair of bolts 48 are formed in the basemember 45. The base member 45 includes a bearing surface block 50 a anda support block 50 b. The bearing surface block 50 a has bearingsurfaces 49, which engage with a first flange surface of the flangeportion 38 a of the optical element 38. The support block 50 b has abearing surface block support mechanism 51, which supports the bearingsurface block 50 a so that the posture of the bearing surface block 50 ais adjustable.

[0077] The bearing surface block 50 a is arranged in such a way that itslongitudinal direction extends along the tangential direction of theoptical element 38. The bearing surfaces 49 are respectively formed onboth longitudinal ends of the bearing surface block 50 a. That is, thebearing surfaces 49 protrude from the surface of the bearing surfaceblock 50 a. Each bearing surface 49 includes a flat surface having apredetermined area and a curved portion, which is formed at theperiphery of the flat surface and has a predetermined radius ofcurvature. The curved portion prevents the bearing surface 49 from beingdamaged when hit by the corners of the flange portion 38 a of theoptical element 38. A layer of gold is formed on the bearing surface 49by plating, vapor deposition or the like in order to increase thecoefficient of friction with respect to the flange portion 38 a.

[0078] To increase the coefficient of friction between the bearingsurface 49 and the flange portion 38 a, the same metal film as thereflection preventing film applied to the surface of the optical element38 is formed on the surface of the flange portion 38 a. For example, asingle layer or multilayer (two layers, four layers or more) of a metalfilm is applied to the surface of the flange portion 38a by vacuum vapordeposition using MgF₂ (magnesium fluoride), AlF₃ (aluminum fluoride),ZrO₂ (zirconia), Al₂O₃ (alumina) or the like. The surface area of theflange portion 38 a may be increased relative to the longitudinaldirection of the bearing surface block 50 a to increase the coefficientof friction between the bearing surface 49 and the flange portion 38 a.

[0079] A plurality of slits 53, which extend through the blocks in thedirection of the X axis in FIG. 7 (i.e., the radial direction of theoptical element 38), are formed between the bearing surface block 50 aand the support block 50 b and in the support block 50 b. A plurality ofneck portions 55 a to 55 d (bent portions) are formed between thebearing surface block 50 a and the support block 50 b and on the supportblock 50 b. The neck portions 55 a-55 d are formed in the followingmanner. First, the slits 53 are formed with non-machined portions leftbetween the adjoining slits 53. Next, the non-machined portions areengraved from the +X direction and −X direction to form engravedportions 54 and the neck portions 55 a-55 d. A large hole is firstmachined in the −X direction engraving since the machining distance tothe neck portions 55 a-55 d is long.

[0080] To avoid unpredictable distortion from remaining in the neckportions 55 a-55 d, both sides of each neck are formed by the samemachining process, such as mold engraving discharging or mechanicalmachining.

[0081] The support block 50 b is separated into a fixed portion 56, afirst block 57 a, and a second block 58 a by the slits 53, as shown inFIG. 7. The fixed portion 56 is secured to the lens frame 42. The firstneck portion 55 a connects the fixed portion 56 to the first block 57 a,the second neck portion 55 b connects the fixed portion 56 to the secondblock 58 a, the third neck portion 55 c connects the first block 57 a tothe second block 58 a, and the fourth neck portion 55 d connects thesecond block 58 a to the bearing surface block 50 a. The neck portions55 a-55 d have square cross sections.

[0082] The first block 57 a is fixed to the second block 58 a and thefixed portion 56 by the first neck portion 55 a and the third neckportion 55 c. The first neck portion 55 a and the third neck portion 55c hold the first block 57 a so that the first block 57 a is rotatableabout the Y direction (the tangential direction of the optical element)and displacement in the Y direction is restricted. The first block 57 a,the first neck portion 55 a, and the third neck portion 55 c form atangential restriction link 57, which restricts the displacement of theoptical element 38 in the tangential direction.

[0083] The second block 58 a is fixed to the bearing surface block 50 aand the fixed portion 56 by the second neck portion 55 b and the fourthneck portion 55 d. The second neck portion 55 b and the fourth neckportion 55 d hold the second block 58 a so that the second block 58 a isrotatable about the Z direction (the direction parallel to the opticalaxis of the optical element) and displacement in the Z direction isrestricted. The second block 58 a, the second neck portion 55 b, and thefourth neck portion 55 d form an optical axis direction restriction link58, which restricts the displacement of the optical element 38, in thedirection parallel to the optical axis of the optical element.

[0084] The restricting direction of the tangential restriction link 57and the restricting direction of the optical axis direction restrictionlink 58 are substantially perpendicular to each other. In other words,the rotational axis of the tangential restriction link 57 and therotational axis of the optical axis direction restriction link 58 aresubstantially perpendicular to each other.

[0085] The bearing surface block 50 a is connected to the support block50 b by the fourth neck portion 55 d. That is, the tangentialrestriction link 57 and the optical axis direction restriction link 58support the bearing surface block 50 a on the fixed portion 56.

[0086] As shown in FIG. 8, the second and fourth neck portions 55 b, 55d are located along a line that passes through the median positionbetween both bearing surfaces 49. The line is perpendicular to a lineconnecting the two bearing surfaces 49 and is parallel to the Z axis.The first and third neck portions 55 a, 55 c are located along a lineparallel to the line that connects the two bearing surfaces 49. Thethird neck portion 55 c is located near the fourth neck portion 55 d.

[0087] The bearing surface block 50 a is supported on the fixed portion56 by the tangential restriction link 57 and optical axis directionrestriction link 58 in such a way that the bearing surface block 50 a isrotatable about the X direction, Y direction, and Z direction and itsdisplacements in the Y direction and Z direction are restricted.Further, the bearing surface block 50 a is supported by the fourth neckportion 55 d so that it is displaceable in the X direction. In otherwords, the bearing surface block support mechanism 51 includes thetangential restriction link 57, the optical axis direction restrictionlink 58, and the fourth neck portion 55 d, which is displaced in the Xdirection.

[0088] The bearing surface block 50 a has an attachment portion 59having a surface located above the bearing surfaces 49.

[0089] As shown in FIG. 6, the clamp member 46 is located above thebearing surface block 50 a and includes a clamp body 62 and a pad member47. The clamp body 62 will be discussed below with reference to FIGS.10, 11, and 12. FIG. 10 is an enlarged perspective view of the clampbody 62, FIG. 11 is an enlarged perspective view of the clamp body 62 asseen from below, and FIG. 12 is a cross-sectional view of the clamp body62 taken along line 13-13 in FIG. 10.

[0090] The clamp body 62 includes a block 63 and a block supportmechanism 64, which is formed integrally with the block 63. Presssurfaces 65, which face the bearing surfaces 49 of the bearing surfaceblock 50 a, are formed on the two ends of the bottom surface of theblock 63. Each press surface 65 is formed roof-like and has a ridge line65 a extending generally along the tangential direction of the opticalelement 38. The median point of a line connecting two ridge lines 65 aof both press surfaces 65 is positioned above the fourth neck portion 55d.

[0091] The block support mechanism 64 includes a pair of arms 66 and anattachment portion 67. The attachment portion 67 and the block 63 areseparated from each other by a predetermined interval. The attachmentportion 67 is fastened to the attachment portion 59 by means of the padmember 47 by the bolts 68 so that the clamp member 46 is fixed to thebearing surface block 50 a. The pair of arms 66 are formed integrallywith the two sides of the block 63 and the attachment portion 67. Eacharm 66 is formed in a generally U-shaped manner and has an elasticallyvariable length. Each arm 66 is separated by a predetermined distancefrom the inner wall in the attachment groove 44 of the lens frame 42.

[0092] The pad member 47 will now be discussed referring to FIGS. 13 and14. FIG. 13 is a cross-sectional view taken along line 14-14 in FIG. 13.The pad member 47 has a clamped portion 71, which is clamped between theattachment portions 59 and 67, an action portion 72, which is locatedbetween the press surfaces 65 and the flange portion 38 a of the opticalelement 38, and a flexible thin plate portion 73, which connects theclamped portion 71 to the action portion 72 and is elasticallydeformable. Action surfaces 74, which are connected to the flangeportion 38 a of the optical element 38, are defined on the bottomsurface of the action portion 72 in association with the bearingsurfaces 49. Each action surface 74 has a flat portion and a peripheralportion having a predetermined radius of curvature. The peripheralportion of the action surface 74 prevents damage when hit by the cornersof the flange portion 38 a. A layer of gold is applied to the actionsurface 74 by plating, vapor deposition or the like to increase thecoefficient of friction with respect to the flange portion 38 a of theoptical element 38.

[0093] Referring to FIG. 15 and 16, by fastening of the bolts 68, theclamp member 46 elastically deforms the arms 66 and applies pressure tothe press surfaces 65 of the block 63 toward the bearing surface block50 a. The pressure acts on the flange portion 38 a of the opticalelement 38 by means of the action surfaces 74 of the pad member 47. Thisclamps the flange portion 38 a of the optical element 38 between thebearing surfaces 49 and the press surfaces 65.

[0094] As shown in FIGS. 4 to 6, a plurality of weight supportmechanisms 77 are provided on the lens frame 42 between the adjoiningholders 43. The number of the weight support mechanisms 77 is set inaccordance with at least one of the parameters of the optical element38, namely the weight, the thickness, the diameter, the shape, and thematerial of the optical element 38, and the number of the holders 43. Inthe first embodiment, three weight support mechanisms 77 are providedbetween the adjoining holders 43.

[0095] As shown in FIG. 18, each weight support mechanism 77 includes aplate spring 78. The plate spring 78 includes an abutment portion 78a,which abuts on the bottom surface of the flange portion 38 a of theoptical element 38, a pair of support portions 78 b, which are attachedto the lens frame 42 by a pair of bolts 79, and a pair of bent portions78 c, which connect the abutment portion 78a to the support portions 78b. The elasticity of the plate spring 78 supports part of the opticalelement 38.

[0096] The procedures for holding the optical element 38 using theoptical element holding apparatus 39 will now be described.

[0097] As shown in FIG. 4 and FIGS. 15 to 17, the base members 45 areattached to the three attachment grooves 44 of the lens frame 42 by thebolts 48, and the bearing surface blocks 50 a are arranged in therecesses 60. Then, part of the two side surfaces of the bearing surfaceblock 50 a may be held between a pair of flat sandwiching members and betemporarily fastened to the base member 45 to prevent unintentionaldeformation of the bearing surface block 50 a with respect to the fixingportion. The temporary fastening prevents unintentional application ofload to the neck portions 55 a -55 d of the bearing surface blocksupport mechanism 51.

[0098] Next, the optical element 38 is inserted into the lens frame 42,and the flange portion 38 a at the periphery of the optical element 38is arranged on the bearing surfaces 49 of the bearing surface blocks 50a. Then, the temporary fixing plates are separated from the bearingsurface block support mechanism 51. The fourth neck portion 55 dfunction to rotate each bearing surface block 50 a about the tangentialdirection (Y direction) and the radial direction (X direction) of theoptical element 38 along the bottom surface of the flange portion 38 aof the optical element 38. The rotation adjusts the posture of thebearing surface block 50 a in accordance with the state of the flangeportion 38 a of the optical element 38, such as the inclination orwaving of the flange portion 38 a, thereby maximizing the contact areabetween the optical element 38 and the flange portion 38 a.

[0099] Thereafter, each pad member 47 is placed on the top surface ofthe flange portion 38 a of the optical element 38 and the clamp body 62is placed on the top surface of the attachment portion 59 of theassociated bearing surface block 50 a so that the action surfaces 74 ofthe pad member 47 are connected to the top surface of the flange portion38 a of the optical element 38. In this state, each pad member 47 andthe associated clamp body 62 are securely fastened by the pair of bolts68. This causes the press surfaces 65 of the associated block 63 tocontact the top surface of the pad member 47 and elastically deforms thearms 66. As a result, the action surfaces 74 of the pad member 47 pressthe optical element 38.

[0100] The pressure causes the flange portion 38 a of the opticalelement 38 to be clamped between the bearing surfaces 49 and the actionsurfaces 74. In this state, the area of the flange portion 38 acontacting the bearing surfaces 49 and the action surfaces 74 of theoptical element 38 is maximized. This stably holds the optical element38.

[0101] In a state held by the lens frame 42 of the optical elementholding apparatus 39, the optical elements 38 are superimposed as shownin FIG. 3. Since the optical element 38 and the lens frame 42 are formedof different materials, a coefficient of linear expansion may varybetween the optical element 38 and the lens frame 42. Thus, when theoptical element 38 is heated by the irradiation of the exposure light ELfrom the light source 32, the expansion lengths of the optical element38, the lens frame 42 and the lens barrel modules 420 differ from oneanother in the radial direction of the optical element 38.

[0102] When a difference in the expansion length occurs, the cooperativeaction of the restriction links 57 and 58 and the neck portions 55 a -55d of each bearing surface block support mechanism 51 relatively movesthe bearing surface block 50 a and the block 63, which hold the opticalelement 38, in the radial direction of the optical element 38 withrespect to the lens frame 42. The movement absorbs the difference inexpansion length so that a large expansion load will not be applieddirectly to the optical element 38.

[0103] When superimposing a lens frame 42, the lens frame 42 mayslightly be distorted. When the lens frame 42 is distorted, thecooperative action of the restriction links 57 and 58 and the neckportions 55 a -55 d of each bearing surface block support mechanism 51causes the optical element 38 to be held to the lens frame 42 in akinematical manner. This suppresses the influence of the distortion onthe optical element 38.

[0104] A description will now be given of the mechanism that holds theoptical element 38 in a kinematical manner.

[0105]FIG. 19 is a schematic diagram of the holder 43 for the opticalelement 38. Referring to FIG. 19, the rectangle at the periphery of theoptical element 38 indicates the bearing surface block 50 a and theblock 63, the L-like shape indicates the fixed portion 56 of the basemember 45, the two lines respectively indicate the tangentialrestriction link 57 and the optical axis direction restriction link 58,and the dots on the lines respectively indicate the neck portions 55 a-55 d.

[0106] The fixed portion 56 is a bent rigid body having two right-anglerigid body portions 56 a, 56 b. The first end of the tangentialrestriction link 57 is coupled to the right-angle rigid body portion 56a by means of the first neck portion 55 a. The first end of the opticalaxis direction restriction link 58 is coupled to the other right-anglerigid body portion 56 b by means of the second neck portion 55 b. Thesecond end of the tangential restriction link 57 is coupled to theoptical axis direction restriction link 58 by means of the third neckportion 55 c. The second end of the optical axis direction restrictionlink 58 is coupled to the bearing surface block 50 a via the fourth neckportion 55 d.

[0107] Each of the restriction links 57, 58 functions as a rigid body inthe longitudinal direction and does not expand in the longitudinaldirection. Each of the linear body portions 56 a, 56 b, 57, 58 arecoupled by the neck portions 55 a -55 d, which function as rotationalpivots. The cross-sectional area of each of the neck portions 55 a -55 dis considerably smaller than the cross-sectional area of each linearrigid body, and the neck portions 55 a -55 d are easily bent or twistedin every direction within the range where plastic deformation does notoccur, in accordance with the displacements of the rigid bodies. A linkmechanism 80, in which the fixed portion 56 functions as a fixed linkand the restriction links 57, 58 act cooperatively, is formed on eachbearing surface block support mechanism 51.

[0108] A polar coordinate system R-θ-Z in which the optical axis of theoptical element 38 is the Z axis will now be construed. In the linkmechanism 80, the fourth neck portion 55 d, which serves as a point ofconnection between the optical element 38 and the link mechanism 80, isdisplaceable within a predetermined range only in the R direction. Thatis, two degrees of freedom of the optical element 38 are restricted ateach of the three points (fourth neck portion 55 d) fixed to the opticalelement 38, and the posture (determined by six degrees of freedoms) ofthe optical element 38 is mechanically restricted. In other words, theoptical element 38 is held in a kinematical manner.

[0109] A description will now be given of the action of the linkmechanisms 80 that absorbs the thermal deformation of the opticalelement 38. When the optical element 38 is thermally deformed, theoptical element 38 expands or contracts in the radial direction, and aforce that displaces the optical element 38 in the radial direction actson the fourth neck portion 55 d. In response to this force, therestriction links 57, 58 rotate about the line that connects the firstneck portion 55 a and the second neck portion 55 b. The rotationalmotion absorbs the displacement of the optical element 38 and suppressesthe distortion of the optical element 38.

[0110] The optical element holding apparatus 39 of the first embodimenthas the following advantages.

[0111] (1) The holder 43 of the optical element holding apparatus 39that holds the optical element 38 includes the bearing surface block 50a having the bearing surface 49 that engages the flange portion 38 a ofthe optical element 38. The holder 43 further includes the bearingsurface block support mechanisms 51 that supports the bearing surfaceblocks 50 a rotatably about the tangential direction, the optical axisdirection, and the radial direction of the optical element 38.

[0112] The bearing surface block support mechanism 51 changes theposture of each bearing surface 49 in accordance with the shape of theflange portion 38 a of the optical element 38. Thus, the production ofstress on the optical element 38 is suppressed when the flange portion38 a abuts on the bearing surface 49. As a result, the optical element38 is held stably while maintaining the accuracy of the optical surfaceof the optical element 38 in a satisfactory state. Further, satisfactoryimaging performance of the optical element 38 is maintained without theholder 43 having to undergo extremely accurate machining.

[0113] (2) The bearing surface block support mechanism 51 supports theassociated bearing surface block 50 a movably in the radial direction ofthe optical element 38. Accordingly, the thermal deformation of theoptical element 38 is absorbed by the bearing surface block supportmechanisms 51 so that the accuracy of the optical surface of the opticalelement 38 is maintained in a satisfactory state and changes in theimaging performance of the optical element 38 is reduced when theoptical element 38 is thermally deformed.

[0114] (3) The holder 43 is provided with the tangential restrictionlink 57 and the optical axis direction restriction link 58. Thetangential restriction link 57 restricts the movement of the fixedportion 56, which is fixed to the lens frame 42, and the bearing surfaceblock 50 a in the tangential direction of the optical element 38 andpermits the rotation of the fixed portion 56 and the bearing surfaceblock 50 a about the tangential direction. The optical axis directionrestriction link 58 restricts the movement of the fixed portion 56 andthe bearing surface block 50 a in the optical axis direction of theoptical element 38 and permits rotation of the fixed portion 56 and thebearing surface block 50 a in the optical-axial direction. Thetangential restriction link 57 and the optical axis directionrestriction link 58 are rotatably connected to each other.

[0115] At the connecting links of the links 57, 58, displacement inmultiple directions or rotation about these directions are permitted.That is, the bearing surface block 50 a is permitted to move in multipledirections or rotate about these directions. When, for example, the lensframe 42 is distorted, the connecting links allow for the movement orrotation of each bearing surface block 50 a in such a way as to offsetthe distortion, so that the three bearing surface blocks 50 a are heldat their predetermined positions. The holder 43 having the links doesnot require highly accurate machining. This maintains the imagingperformance at a high level in the optical element 38.

[0116] The links 57 and 58 of the bearing surface block supportmechanism 51 are provided in the tangential direction and optical axisdirection of the optical element 38. This simplifies the structure ofthe link mechanism and facilitates the designing of the link mechanism.

[0117] (4) The fixed portion 56, the bearing surface block 50 a, thetangential restriction link 57, and the optical axis directionrestriction link 58 are coupled by means of the neck portions 55 a -55d, which function as rotational pivots. The cross-sectional area of eachof the neck portions 55 a-55 d is smaller than the cross-sectional areaof each of the fixed portion 56, the bearing surface block 50 a, thetangential restriction link 57, and the optical axis directionrestriction link 58.

[0118] This enables the neck portions 55 a-55 d, the fixed portion 56,the bearing surface block 50 a, the tangential restriction link 57, andthe optical axis direction restriction link 58 to be formed integrally.Accordingly, the holder has a simplified structure even though thenumber of components is not increased.

[0119] (5) The fourth neck portion 55 d that is connected to the bearingsurface block 50 a extends through the median position between the twobearing surfaces 49 and is arranged along a line parallel to the opticalaxis of the optical element 38. This changes the posture of the bearingsurface 49 in a stable manner.

[0120] (6) The bearing surface block 50 a has two bearing surfaces 49formed with a predetermined distance in between at the position thatfaces the flange portion 38 a of the optical element 38. Therefore, theoptical element 38 formed of a glass material, such as synthesizedquartz, which has a relatively large fracture strength is held in areliable and stable manner by the two bearing surfaces 49.

[0121] (7) A gold layer is plated or vapor-deposited on the bearingsurfaces 49 of the bearing surface block 50 a and the action surface 74of the pad member 47 in order to increase the coefficient of frictionwith respect to the flange portion 38 a of the optical element 38. Thissuppresses sliding of the bearing surfaces 49 and the action surfaces 74with respect to the flange portion 38 a of the optical element 38 andholds the optical element 38 in a further stable state.

[0122] (8) The block 63 of the clamp member 46 includes the presssurfaces 65, the ridge lines 65 a of which extend in the tangentialdirection of the optical element 38. The press surfaces 65 press theflange portion 38 a of the optical element 38 by means of the actionportion 72 of the pad member 47. As a result, the flange portion 38 a ofthe optical element 38 is held between the block 63 and the bearingsurface block 50 a. In this state, the fourth neck portion 55 d islocated below the line that connects the ridge lines 65 a of the twopress surfaces 65.

[0123] This suppresses the generation of the moment originated from thepressure applied to the fourth neck portion 55 d, allowing the opticalelement 38 to be held stably.

[0124] (9) The bearing surface block 50 a and the bearing surfaces 49are formed integrally with the restriction links 57, 58, the neckportions 55 a-55 d, and the fixed portion 56.

[0125] Therefore, the bearing surface block 50 a and the support block50 b are formed integrally from the same material. There is no junctionmade of another material that is formed between the bearing surfaceblock 50 a and the support block 50 b. Thus, distortion is unlikely tooccur. Due to the integration of the bearing surface block 50 a and thesupport block 50 b, the holder 43 is relatively small.

[0126] (10) The lens barrel 37 is formed by superimposing the lensbarrel modules 420, each of which houses the optical element 38 held bythe optical element holding apparatus 39. This permits a plurality ofoptical elements 38 to be held stably while preventing the imagingperformances of the optical elements 38 from decreasing so that theimaging performance of the entire lens barrel 37 is maintained at asatisfactory level.

[0127] (11) The exposure apparatus 31 has the projection optical system35, which includes the lens barrel 37. This improves the exposureaccuracy of the exposure apparatus 31.

[0128] (Second Embodiment)

[0129] An optical element holding apparatus 39 according to a secondembodiment of the invention will be described below, centering on thedifferences from the first embodiment.

[0130] In the second embodiment, as shown in FIGS. 21 to 23, a bearingsurface 91 of the bearing surface block 50 a and an action surface 92 ofthe pad member 47 are formed extending in the tangential direction ofthe optical element 38.

[0131] A housing hole 93 is formed in the centers of the bearing surface91 and the action surface 92. A contractible adhesive which volumeslightly contracts when hardening is charged in the housing hole 93. Theflange portion 38 a of the optical element 38 is connected to thebearing surface 91 and the action surface 92 by the adhesive charged inthe housing hole 93. An adhesive charging hole 94 which is connected tothe housing hole 93 may be formed in the bottom of the housing hole 93as shown by the broken lines in FIG. 22.

[0132] The optical element holding apparatus 39 of the second embodimenthas the following advantages in addition to advantages (1) to (5) and(7) to (11) of the first embodiment.

[0133] (12) The bearing surface 91 and the action surface 92 are formedto extend in the tangential direction of the optical element 38.

[0134] Therefore, when holding an optical element 38 formed of a glassmaterial, such as fluorite, which has a relatively small fracturestrength, the stress resulting from the holding is dispersed. Thisprevents the optical element 38 from being damaged by concentratedstress.

[0135] (13) The housing hole 93, which the adhesive is housed in, isformed in the centers of the bearing surface 91 and the action surface92.

[0136] Accordingly, the adhesive charged in the housing hole 93 connectsthe flange portion 38 a of the optical element 38 to the bearing surface91 and the action surface 92, and the hardening of the adhesive engagesthe flange portion 38 a of the optical element 38 with the bearingsurface 91 and the action surface 92. In this state, the use of thecontractible adhesive prevents the flange portion 38 a of the opticalelement 38 from being compressed and holds the optical element 38 in astable manner.

[0137] In the first and second embodiments, the pad members 47 may beomitted and the block 63 may be pressed directly against the flangeportion 38 a. In this case, it is desirable that the press surfaces 65of the block 63 be flat like the bearing surfaces 49.

[0138] In the first embodiment, the bearing surface 49 may be formed onthe entire surface of the bearing surface block 50 a that faces theoptical element 38. Alternatively, three or more bearing surfaces 49 maybe formed. The press surface 65 of the block 63 may also be formed onthe entire surface of the block 63 that faces the optical element 38.Alternatively, three or more press surfaces 65 may be formed.

[0139] An elastic member, such as a plate spring or a coil spring, maybe used in lieu of the arms 66 of the clamp body 62 to apply pressure tothe block 63.

[0140] Each weight support mechanism 77 may be a plate spring formed bythe abutment portion 78 a and the support portions 78 b.

[0141] Instead of plating the bearing surfaces 49 and the actionsurfaces 74 with gold, metal, such as tin, indium, aluminum, or brass,may be applied through metal vapor deposition, plating, welding or thelike. The coefficient of friction may be improved by performing etchingor grinding to roughen the bearing surfaces 49 and the action surfaces74.

[0142] (Third Embodiment)

[0143] An optical element holding apparatus 139 according to a thirdembodiment of the present invention will be described below withreference to the accompanying drawings.

[0144]FIG. 23 is a perspective view of the optical element holdingapparatus 139, FIG. 24 is a plan view of the optical element holdingapparatus 139, FIG. 25 is a side view of the optical element holdingapparatus 139, and FIG. 26 is a cross-sectional view taken along theline 26-26 in FIG. 25. The optical element holding apparatus 139includes a frame 142, three flexure members 41, a lens frame 40, andholders 43. The three flexure members 41 are fixed to the frame 142 atequiangular distances. The lens frame 40 is fixed to the top surfaces ofthe flexure members 41, and the three holders 43 are provided on thelens frame 40 at equiangular distances.

[0145] The structure of the lens frame 40 is similar to that of the lensframe 42 of the optical element holding apparatus 39 discussed in thefirst and second embodiments but differs from the first and secondembodiments in that, as shown in FIG. 38, quadratic prism-likeposition-detecting projections 76 are formed on the peripheral surfaceof the lens frame 40 in the vicinity of the attachment grooves 44. Flatflexure junction portions 177 for connecting the flexure members 41 arearranged on the top surface of the lens frame 40 between the adjoiningholders 43. The flexure junction portions 177 differ from the aboveembodiments in that they extend outward from the lens frame 40. Thestructure of the holder 43 is similar to that of the first and secondembodiments.

[0146] The structure of the frame 142 will be discussed below referringto FIGS. 28 to 33. FIG. 28 is a perspective view of the frame 142, FIG.29 is a partly enlarged plan view of the frame 142, and FIG. 32 is apartial enlarged side view of the frame 142.

[0147] As shown in FIG. 28, the frame 142 is annular and formed ofmetal, such as steel or aluminum. As shown in FIGS. 28 to 30, threeflexure attaching portions 80 for attachment of the flexure members 41are formed on the top surface of the frame 142 at equiangular distances.Three flexure housing recesses 81, which house the respective flexuremembers 41 when the frames 142 are superimposed, are formed in eachframe 142 between the adjacent flexure attaching portions 80. Eachflexure housing recess 81 includes a body housing portion 81a forhousing an associated flexure body 84 and a lever housing portion 81 bfor housing various drive levers 85 a, 85 b. The flexure attachingportions 80 and the flexure housing recesses 81 are formed alternatelyin the circumferential direction of the frame 142. In other words, theflexure housing recess 81 is formed between adjacent flexure attachingportions 80.

[0148] As shown in FIG. 28, attachment seats 83, which receivelens-chamber position detecting mechanisms 82, are formed on theperipheral surface of the frame 142 in the vicinity of the flexurehousing recesses 81. The lens-chamber position detecting mechanism 82(see FIG. 24), which is of, for example, a capacitance detection typeand has an L-like shape, is attached to the attachment seat 83. When thelens frame 40 is mounted onto the frame 142 by means of the flexuremembers 41, the lens-chamber position detecting mechanisms 82 arearranged facing the position-detecting projections 76 of the lens frame40 with a predetermined distance in between. When the lens frame 40 ismoved relative to the frame 142, each position-detecting projection 76is displaced with respect to the associated lens-chamber positiondetecting mechanism 82 and the displacement amount is detected by thelens-chamber position detecting mechanism 82.

[0149] The flexure member 41 will now be discussed with reference toFIGS. 29 to 33. As shown in FIGS. 28-30, each flexure member 41 includesthe flexure body 84, a vertical drive lever 85 a, and a horizontal drivelever 85 b. The vertical and horizontal drive levers 85 a, 85 b formpart of a displacement member and a transmission portion.

[0150] Each flexure body 84 is held between the associated flexurejunction portion 177 of the lens frame 40 and the associated flexureattaching portion 80 of the frame 142. The flexure body 84 has aconnection block 84 a, which fixes the associated flexure junctionportion 177 of the lens frame 40 with a bolt 98, and a flexure supportblock 84 b, which includes a connection-block support mechanism 92 forsupporting the connection block 84 a so that its posture is adjustable.

[0151]FIG. 31 is a partial enlarged side view of the attaching portionof the flexure body 84, and FIG. 32 is a cross-sectional view takenalong the line 32-32 in FIG. 29. FIG. 33 is a partial enlargedcross-sectional view showing the cross sections of the flexure member 41and the frame 142.

[0152] As shown in FIGS. 31 to 33, each flexure body 84, which has agenerally rectangular parallelepiped shape, includes plural first slits86 and a second slit 87 formed between the connection block 84 a and theflexure support block 84 b and in the flexure support block 84 b. Thefirst slits 86 and second slit 87 extend in the X direction of FIG. 33.A reference hole 84 c is formed in the lower portion of the flexure body84, each first slit 86 is formed above the reference hole 84 c, and thesecond slit 87 is formed below the reference hole 84 c. A plurality offlexure neck portions 89a to 89d, which serve as rotational pivots andnotch springs are formed between the connection block 84 a and theflexure support block 84 b and on the flexure support block 84 b. Theflexure neck portions 89 a-89 d are formed in the following manner.

[0153] First, the slits 86, 87 are formed with non-machined portionsleft between the adjoining slits 86, 87. Next, the non-machined portionsof the first slits 86 are subjected to engraving from the +X direction(toward the top surface of the sheet of FIG. 33) and −X direction(toward the back surface of the sheet of FIG. 33), thus forming engravedportions 86 a and the flexure neck portions 89 a-89 d. The engravedportions 86 a are formed on both sides of the flexure neck portions 89a-89 d, and each include a rectangular though hole 88 a, which extendsin the radial direction of the optical element 38. To form the engravedportions 86 a and the flexure neck portions 89 a-89 d, holes larger thanthe engraved portions 86 a and the flexure neck portions 89 a-89 d areformed in both sides of the flexure support block 84 b.

[0154] To prevent unpredictable distortion from remaining in the flexureneck portions 89 a-89 d, both sides of each of the flexure neck portions89 a-89 d are formed though the same kind of machining, such as engravedischarging or mechanical machining, in the depth direction of thethrough holes 88 a.

[0155] A pair of circular through holes 88 b, which extend in the radialdirection of the optical element 38, are formed with a predetermineddistance provided between two non-machined portions of the second slit87. First and second thin portions 90 a, 90 b, which serve as aconversion mechanism and a first notch spring, are formed between thetwo circular through holes 88 b.

[0156] The flexure support block 84 b is separated into a flexure fixingportion 91, a first restriction block 93 a, a second restriction block94 a, a first drive block 94 a, and a second drive block 96 a by thefirst and second slits 86, 87. The flexure fixing portion 91 is securedto the flexure attaching portion 80 of the frame 142 by bolts 97 (referto FIGS. 28 and 29).

[0157] The first flexure neck portion 89 a connects the first driveblock 94 a to the first restriction block 93 a, the second flexure neckportion 89b connects the second drive block 96 a to the secondrestriction block 94 a, the third flexure neck portion 89c connects thefirst restriction block 93 a to the second restriction block 94 a, andthe fourth flexure neck portion 89 d connects the first restrictionblock 93 a to the connection block 84 a. The flexure neck portions 89a-89 d have square cross sections considerably smaller than the crosssections of the drive blocks 94 a and 96 a and the connection block 84a.

[0158] The first restriction block 93 a is fixed to the first driveblock 94 a and the connection block 84 a by the first flexure neckportion 89 a and the fourth flexure neck portion 89 d. The first flexureneck portion 89 a and the fourth flexure neck portion 89 d hold thefirst restriction block 93 a rotatable around the Z direction (theoptical axis direction of the optical element 38) and restrict itsdisplacement in the Z direction. The first restriction block 93 a, thefirst flexure neck portion 89 a, and the fourth flexure neck portion 89d form a vertical restriction link 93, which restricts the displacementof the optical element 38 in the vertical direction (the optical axisdirection).

[0159] The second restriction block 94 a is fixed to the second driveblock 96 a and the first restriction block 93 a by the second flexureneck portion 89 b and the third flexure neck portion 89 c. The secondflexure neck portion 89 b and the third flexure neck portion 89 c holdthe second restriction block 94 a rotatable about the Y direction (thetangential direction of the optical element 38) and restrict itsdisplacement in the Y direction. The second restriction block 94 a, thesecond flexure neck portion 89 b, and the third flexure neck portion 89c form a horizontal restriction link 94, which restricts thedisplacement of the optical element 38 in the horizontal direction (thetangential direction).

[0160] The restricting direction of the vertical restriction link 93 issubstantially perpendicular to the restricting direction of thehorizontal restriction link 94. In other words, the rotational axis ofthe vertical restriction link 93 and the rotational axis of thehorizontal restriction link 94 are substantially perpendicular to eachother.

[0161] The connection block 84 a is connected to the flexure supportblock 84 b by means of the fourth flexure neck portion 89 d. That is,the connection block 84 a is supported by the vertical restriction link93 and the horizontal restriction link 94.

[0162] As shown in FIGS. 31 to 33, the first and fourth flexure neckportions 89 a, 89 d are located on a line that substantially extendsthrough the center of the connection block 84 a and is parallel to the Zaxis. The second and third flexure neck portions 89 b, 89 c are locatedon a line that is substantially parallel to the surface of theconnection block 84 a. The third flexure neck portion 89 c is locatednear the fourth flexure neck portion 89 d.

[0163] In the flexure body 84, the connection block 84 a is supported onthe first and second drive blocks 94 a and 96 a by the verticalrestriction link 93 and the horizontal restriction link 94 in such a waythat the connection block 84 a is rotatable in the X direction, Ydirection, and Z direction and its displacements in the Y direction andZ direction are restricted. Further, the connection block 84 a issupported so that it is displaceable in the X direction by the fourthflexure neck portion 89 d.

[0164] The first drive block 94 a is fixed to the first restrictionblock 93 a by the first flexure neck portion 89 a and to the flexurefixing portion 91 by the first thin portion 90 a. The first thin portion90 a serves as the conversion mechanism and the first notch spring. Thevertical drive lever 85 a, which extends in the tangential direction ofthe optical element 38 is formed integrally on the first drive block 94a. The first thin portion 90 a transmits the movement of the verticaldrive lever 85 a in the optical axis direction (vertical direction) ofthe optical element 38 to the first flexure neck portion 89 a, whichserves as a second notch spring. The first drive block 94 a, the firstflexure neck portion 89 a, and the first thin portion 90 a form avertical drive link 95 which transmits the movement of the verticaldrive lever 85 a in the vertical direction, to the vertical restrictionlink 93.

[0165] The second drive block 96 a is connected to the secondrestriction block 94 a by the second flexure neck portion 89 b and tothe flexure fixing portion 91 by the second thin portion 90 b. Thehorizontal drive lever 85 b, which extends in the tangential directionof the optical element 38, is formed integrally on the second driveblock 96 a. The second thin portion 90 b serves as the conversionmechanism and a third notch spring. The second thin portion 90 btransmits the movement of the horizontal drive levers 85 b in theoptical axis direction (vertical direction) of the optical element 38 tothe second flexure neck portion 89 b, which serves as a fourth notchspring. The second drive block 96 a, the second flexure neck portion 89b, and the second thin portion 90 b form a horizontal drive link 96,which converts the vertical movement of the horizontal drive lever 85 bto a horizontal movement and transmits the horizontal movement to thehorizontal restriction link 94.

[0166] The first flexure neck portion 89 a is located on an imaginaryline that extends through the center of the first thin portion 90 a andin the tangential direction of the optical element 38. The secondflexure neck portion 89 b is located on an imaginary line that extendsthrough the center of the second thin portion 90 b and in the opticalaxis direction of the optical element 38.

[0167] As shown in FIGS. 28 to 30 and FIG. 32, adjusting washers 99 andadjusting buttons 100 are fixed to the distal ends of the drive levers85 a, 85 b in a replaceable manner by replacing members 101 (e.g., boltsand plugs). The adjusting washers 99 and adjusting buttons 100 formmoving-amount setting means. A plurality of adjusting washers 99 areprepared beforehand in such a way that the thickness can be adjusted inunits of, for example, 1 μm. A plurality of adjusting buttons 100 areprepared beforehand in such a way that the thickness can be adjusted inunits of, for example, 10 μm. In other words, the adjusting washers 99are used for fine adjustment, and the adjusting buttons 100 are used forrough adjustment. The selective combination of the adjusting washers 99and adjusting buttons 100 adjusts the distances between the drive levers85 a and 85 b and the frame 142, thereby setting the amounts of movementof the drive levers 85 a and 85 b. The drive levers 85 a and 85 b havepredetermined lengths. Thus, the movement amounts of the proximal endportions of the drive levers 85 a, 85 b are smaller than the movementamounts of the distal end portions.

[0168] Lift levers 102, which serve as manipulation portions areprovided near the adjusting washers 99 and adjusting buttons 100 and onthe top surface of the frame 142 in such a way as to be verticallymovable toward and away from the drive levers 85 a and 85 b. Returnsprings 103, which are extension springs, are attached between the drivelevers 85 a, 85 b and the frame 142 in the vicinity of the lift levers102. The return springs 103 urge the drive levers 85 a, 85 b toward theframe 142 so that when the lift levers 102 are not contacting the drivelevers 85 a, 85 b, the distal ends of the drive levers 85 a, 85 bcontact the top surfaces of the adjusting buttons 100. The drive levers85 a, 85 b are separated from the frame 142 against the biasing force ofthe extension springs by moving the lift lever 102 away from the frame142, or in an upward direction, while the lift lever 102 is in contactwith the drive levers 85 a, 85 b. This separates the drive levers 85 a,85 b from the adjusting buttons 100. The adjusting buttons 100 and theadjusting washers 99 are replaced when the drive levers 85 a, 85 b areseparated from the adjusting button 100 in this manner. After thereplacement of the adjusting buttons 100 and the adjusting washers 99 iscompleted, the lift lever 102 is returned to its original position. Thisresults in the biasing force of the extension springs causing the drivelevers 85 a, 85 b to contact the upper surfaces of the adjustingbuttons.

[0169] As shown in FIGS. 23 and 28, a connection surface 40 a connectedwith another frame 142 is defined on the frame 142. A plurality ofoptical element holding apparatuses 139 are superimposed with a phasedifference of 180° between one another by the connection surfaces 40 aof the frames 142 by means of a space adjusting spacer. In this state,the lens frame 40 of the underlying optical element holding apparatus139 is housed in the frame 142 of the overlying optical element holdingapparatus 139. The flexure members 41 of the underlying optical elementholding apparatus 139 are housed in the flexure housing recesses 81 ofthe frame 142 of the overlying optical element holding apparatus 139.

[0170] The operation of the optical element holding apparatus 139 willnow be discussed. In the optical element holding apparatus 139 of thethird embodiment, the lens frame 40, which serve as a support member forsupporting an optical element 38, and the frame 142, which serves as afixing portion for fixing the lens frame 40 to a lens barrel module 37a, are connected by the three flexure members 41. The lens barrel module37 a refers to the other superimposed frames 142. Another mode of theflexure member 41 of the optical element holding apparatus 139 is shownin FIG. 35. As shown in FIG. 35, each flexure member 41 has two rigidbodies 106 a, 106 b, rotational pivots 107 a, 107 b, provided on the twoends of the rigid body 106 b, and rotational pivots 107 c, 107 dprovided on the two ends of the rigid body 106 a. In other words, theentire optical element holding apparatus 139 includes six rigid bodiesand rotational pivots provided on the two ends of each rigid body. Therotation in three directions refers to the rotations about an axisextending through the longitudinal direction of each rigid body 106 andtwo axes perpendicular to the axis and to each other.

[0171] Further, the rigid bodies 106 a, 106 b are arranged so that whena straight line connects the rotational pivots 107 a, 107 b, of therigid body 106 a and a straight line connects the rotational pivots 107c, 107 d of the rigid body 106 b (in the present embodiment, there aresix straight lines since there are three combinations of the rigidbodies 106 a, 106 b), three or more straight lines do not intersect thesame point. Since the rotational pivot 107 b, at one end of the rigidbody 106 a and the rotational pivot 107 d of the rigid body 107 d arearranged in the vicinity of each other, it seems as a whole that therotational pivots 107 b, 107 d are integral. In other words, the tworigid bodies 106 a, 107 b, share the same rotational pivot.

[0172] Further, a position adjusting mechanism 108, which serves as adistance adjusting mechanism for adjusting the positions of the rigidbodies 106 a, 106 b relative to the frame 142, is arranged at the otherend of each of the rigid bodies 106 a, 106 b. The position adjustingmechanism 108 displaces the positions of the end portions of each rigidbody to adjust the distance between the frame 142 and the lens frame 40.

[0173] When comparing the third embodiment with the above embodiments,the rigid body 106 a corresponds to the second restriction block 94 aand the rigid body 106 b corresponds to the first restriction block 94b. Further, the rotational pivot 107 a corresponds to the second flexureneck portion 89 b, the rotational pivot 107 b, corresponds to the secondflexure neck portion 89 a, the rotational pivot 107 c corresponds to thesecond flexure neck portion 89 c, and rotational pivot 107 d correspondsto the second flexure neck portion 89 d. The third flexure neck portion89 c at one end of the second restriction block 94 a is connected to thevicinity of the fourth flexure neck portion 89 d at one end of the firstrestriction block 93 a Thus, as a whole, the two flexure neck portions89 c, 89 d appears as integral rotational pivots 107 b, 107 d. Further,the position adjusting mechanism 108 corresponds to the adjustingwashers 99, the adjusting buttons 100, the vertical drive levers 85 a,the horizontal drive levers 85 b, the first drive block 94 a, and thesecond drive block 96 a.

[0174] For designing reasons, the displacement direction of eachrestriction block 93 a, 94 a is vertical or lateral and differs from thediagonal direction of the two rigid bodies in the above model but aresubstantially the same when combined.

[0175] The operation of the optical element holding apparatus 139 willnow be discussed in detail. FIG. 36 exemplarily shows only the linkmechanism 104 of a single flexure body 84.

[0176] When the tip end portion of the vertical drive lever 85 a isactuated in the vertical direction by a predetermined drive force F1,the first thin portion 90 a converts the drive force to a rotatingmoment M1 about the radial axis of the optical element 38. The rotatingmoment M1 is converted to linear drive force in the vertical directionof the first flexure neck portion 89 a on the extension of a center lineL1 of the first thin portion 90 a via the first drive block 94 a. Thelinear drive force is transmitted to the connection block 84 a by meansof the first restriction block 93 a and the fourth flexure neck portion89 d. This moves the optical element 38 in the lens frame 40 in theoptical axis direction.

[0177] Next, when the tip end portion of the horizontal drive levers 85b is actuated in the vertical direction by a predetermined drive forceF2, the second thin portion 90 b converts the drive force to a rotatingmoment M2 about the radial axis of the optical element 38. The rotatingmoment M2 is converted to linear drive force in the horizontal directionof the second flexure neck portion 89 b positioned on the extension of acenter line L2 of the second thin portion 90 b via the second driveblock 96 a. The linear drive force is transmitted to the connectionblock 84 a by means of the second restriction block 94 a, the thirdflexure neck portion 89 c, and the fourth flexure neck portion 89 d.This moves the optical element 38 in the lens frame 40 in the tangentialdirection.

[0178] When the tip end portions of the drive levers 85 a, 85 b aredriven in the vertical direction by the predetermined drive forces F1,F2, the two drive forces are synthesized by the restriction links 93 and94 and the third flexure neck portion 89 c. A polar coordinate R-θ-Zsystem in which the optical axis of the optical element 38 is the Z axiswill now be discussed. The θ coordinate and Z coordinate of the thirdflexure neck portion 89 c change in accordance with the movements of thedrive levers 85 a and 85 b. As the movements of the third flexure neckportion 89 c in the X and Y directions are restricted by the restrictionlinks 93 and 94, the third flexure neck portion 89 c can slightly rotateabout a line L3, which connects the first flexure neck portion 89 a tothe second flexure neck portion 89 b. That is, the third flexure neckportion 89 c has some degree of freedom to move in the direction of theR coordinate (the radial direction of the optical element 38).Therefore, the parallel shifts of the polar coordinates θ and Z of thethird flexure neck portion 89 c that is a fixed point with respect tothe lens frame 40 are restricted to a predetermined position and theparallel shift of the polar coordinate R is permitted. Since the thirdflexure neck portion 89 c is a rotational pivot, the third flexure neckportion 89 c is free to rotate about the polar coordinates R, θ, and Z.

[0179] The aforementioned movements and restrictions independently occuron each of the three flexure bodies 84. Therefore, the freedom of thethree fixed points (the third flexure neck portions 89 c) in twodirections is restricted. That is, the posture (six degrees of freedom)of the lens frame 40 is restricted based on the mechanics. As theposture of the lens frame 40 corresponds 1:1 to the movement amounts ofthe drive levers 85 a, 85 b, the posture of the optical element 38 heldin the lens frame 40 can be adjusted freely without applying excessiveforce and distortion to the optical element 38.

[0180] The lens frame 40 is supported in the frame 142 by the individualflexure members 41 in a kinematical manner. A polar coordinate systemR-Q-Z, in which the center of the optical element 38 is the origin, theoptical-axial direction of the optical element 38 is the Z axis, theradial direction of the optical element 38 is the R axis, and thecircumferential direction of the optical element 38 is the Q axis, willnow be discussed. In each link mechanism 104, the third flexure neckportion 89 c is displaceable in the directions of the R, Q and Z axeswithin predetermined ranges. Further, the lens frame 40 can be tilted inan arbitrary direction with respect to the frame 142 by properlychanging the height of the third flexure neck portion 89 c in each linkmechanism 104 from the frame 142. The lens frame 40 is thereforesupported on the frame 142 in such a way as to be movable in thedirections of the R, Q, and Z axes and rotatable around the R axis, theQ axis, and the Z axis.

[0181] An example in which the optical element 38 is moved within aplane perpendicular to its optical axis by the three link mechanisms 104will now be discussed with reference to FIG. 37. If the third flexureneck portion 89 c of a link mechanism 104 c is moved to a point MP by apredetermined distance, in accordance with the movement, the center O ofthe lens frame 40 moves by a distance of ⅔ of the predetermined distanceof the link mechanism 104 c around an intersection IP of tangentiallines TL of the third flexure neck portions 89 c of link mechanisms 104a, 104 b.

[0182] This is because of the following reasons. The positionalrelationship of four points, namely, the center O of the lens frame 40,the third flexure neck portions 89 c of the link mechanisms 104 a, 104b, and the intersection IP of the tangential lines TL will now bediscussed. The four points form two right triangles, which have interiorangles of 30°, 60° and 90° and are congruent with each other. When thedistance (radius) between the center O of the lens frame 40 and eachthird flexure neck portion 89 c is set to 1, the distance between thecenter O of the lens frame 40 and the intersection IP is twice theradius. Thus, the distance between the intersection IP and the thirdflexure neck portion 89 c of the link mechanism 104 c is three times theradius. Therefore, the center 0 of the optical element 38 moves to apoint MP′ by a distance of ⅔ of the moving distance of the third flexureneck portion 89 c of the link mechanism 104 c.

[0183] A description will now be given of the procedures for assemblingthe optical element holding apparatus 139.

[0184] First, as shown in FIG. 38, the base members 45 of the holders 43are fastened to the surface of the lens frame 40 opposite to theattachment grooves 44 by bolts, which are not shown. The bearing surfaceblock support mechanisms 51 of the base members 45 are temporarilysecured to the base members 45 by sandwich members 108. Each sandwichmember 108 prevents a load from being unintentionally applied to therestriction links 57, 58 and the neck portions 55 a-55 d of theassociated bearing surface block support mechanism 51 until the opticalelement 38 is mounted.

[0185] Next, the optical element 38 is housed in the lens frame 40 andthe flange portion 38 a of the optical element 38 is placed on thebearing surfaces 49 of the bearing surface blocks 50 a of the basemembers 45. The optical element 38 is positioned with respect to thelens frame 40 using a centering machine, and the pad members 47 and theclamp members 46 are fastened to the attachment portions 59 of the basemembers 45 by the bolts 68. As a result, the flange portion 38 a of theoptical element 38 is held between the bearing surfaces 49 and the presssurfaces 65. Then, the sandwich members 108 are separated from the basemembers 45 and the postures of the bearing surface blocks 50 a areadjusted in accordance with the shape of the flange portion 38 a of theoptical element 38 by operating the bearing surface block supportmechanisms 51. This holds the optical element 38 in a stable state.

[0186] Next, the optical surface of the optical element 38 is inspected.When the inspection shows a change in the optical surface that isgreater than a predetermined value, the bearing surface block supportmechanisms 51 are temporarily secured by the sandwich members 108 againand the mounting of the optical element 38 is performed again.

[0187] Then, the flexure bodies 84 are securely fastened to the flexureattaching portions 80 by the bolts 97, as shown in FIG. 28. Then,shoulder pad members 109 are attached in such a way as to sandwich theconnection blocks 84 a of the flexure bodies 84. Each shoulder padmember 109 prevents a load from being unintentionally applied to therestriction links 93, 94, the drive links 95, 96, the flexure neckportions 89 a-89 d, and the thin portions 90 a, 90 b of the associatedflexure body 84 until the lens frame 40 is assembled.

[0188] Next, the flexure junction portions 177 are fastened to theconnection blocks 84 a of the flexure bodies 84 by the bolts 98 totemporarily fix the lens frame 40 on the frame 142. In this state, theframe 142 is placed on the centering machine and rotated during whichthe vibration of the optical axis of the optical element 38 is observed.Based on the observation results, the bolts 98 are loosened to adjustthe position of the lens frame 40 after which the lens frame 40 istemporarily secured again by the bolts 98. This adjustment is repeateduntil the vibration of the optical axis of the optical element 38becomes subtle. When the vibration of the optical axis of the opticalelement 38 is substantially eliminated, the bolts 98 are fully fastenedto fix the lens frame 40 onto the frame 142 by means of the flexurebodies 84.

[0189] Then, the shoulder pad members 109 are removed. This obtains inthe optical element holding apparatus 139 of FIG. 24. The frame 142 isrotated on the centering machine again in this state and the table ofthe centering machine is shifted in parallel or tilted to completelyeliminate the vibrations of the optical axis of the optical element 38.In this state, the amount of eccentricity of the outside diameter of thelens frame 40 and the amount of inclination of the end face thereof thatare detected by the centering machine are recorded. Using those piecesof information, the combination of the number of the adjusting washers99 and the number of the adjusting buttons 100 that eliminates theeccentricity amount and the inclination amount is computed by a computerbased on a special software program. Based on the computation results,the adjusting washers 99 and the adjusting buttons 100 are selectivelyattached. Finally, the entire assembly is rotated by the centeringmachine and the vibration of the optical axis of the optical element 38is checked again.

[0190] Then, the lens barrel 37 is assembled by superimposing multipleoptical element holding apparatuses 139 with phases offset from oneanother by 180°, as shown in FIG. 34.

[0191] The optical element holding apparatus 139 of the third embodimenthas the following advantages.

[0192] (1) The lens frame 40, which holds the optical element 38, andthe frame 142 are connected by means of the three flexure bodies 84.Each flexure body 84 is provided with the drive levers 85 a, 85 b thatproduce three movements in a coordinate system, which uses the center ofthe optical element 38 as an origin, the optical axis direction of theoptical element 38 as the Z axis, the radial axis as the R axis, and thecircumferential direction as the Q axis, and rotations about the threecoordinate axes R, Q, and Z.

[0193] When predetermined drive forces are applied to the drive levers85 a, 85 b, each flexure body 84 functions to give the optical element38 six degrees of freedom of motion or the three movements along thecoordinate axes R, Q, and Z and three rotations around the three axes R,Q, and Z. That is, the optical element 38 is held in a kinematicalmanner. Therefore, the flexure bodies 84 function to finely adjust theposture of the optical element 38 and easily and accurately position theoptical element 38 without having to perform accurate machining.

[0194] (2) The three flexure bodies 84 are arranged at equiangulardistances around the optical element 38. The positioning of the threeflexure bodies 84 simplifies the structure for positioning the opticalelement 38 and holds the optical element 38 in a stable state.

[0195] (3) Each of the three flexure bodies 84 has the flexure fixingportion 91, which is fixed to the frame 142, and the connection block 84a, which is connected to the lens frame 40. The vertical restrictionlink 93 and the horizontal restriction link 94 are provided to restrictthe movements of the flexure fixing portion 91 and the connection block84 a in different directions (the vertical direction and horizontaldirection) and to support the flexure fixing portion 91 and theconnection block 84 a in a manner rotatable in different directions. Theflexure fixing portion 91 and the restriction links 93 and 94 providethe connection block 84 a with six degree of freedom of motion. Thisstructure permits the optical element 38 to be positioned easily andaccurately.

[0196] (4) The horizontal restriction link 94 restricts the horizontalmovement of the flexure fixing portion 91 and the connection block 84 aand supports the flexure fixing portion 91 and the connection block 84 arotatable in the horizontal direction. The vertical restriction link 93restricts the vertical movement of the flexure fixing portion 91 and theconnection block 84 a and supports the flexure fixing portion 91 and theconnection block 84 a rotatable in the vertical direction. The linkmechanism formed by the horizontal restriction link 94 and the verticalrestriction link 93 simplify the structure of the flexure body 84.

[0197] (5) The flexure fixing portion 91 and the connection block 84 aare coupled to the restriction links 93, 94 by the flexure neck portions89 a-89 d. This transmits the movement of the restriction links 93, 94to the flexure fixing portion 91 and the connection block 84 a with asimple structure.

[0198] (6) The drive force in the vertical direction applied to thehorizontal drive lever 85 b is converted to the horizontal drive forceby the conversion mechanism, which includes the second thin portion 90 band the second flexure neck portion 89 b. This increases the degree offreedom of design of the flexure body 84. The vertical movement outsidethe flexure body 84 moves the optical element 38 horizontally. When theoptical element 38 is housed in the lens frame 40, therefore, theconversion mechanism is particularly effective.

[0199] (7) The drive force in the vertical direction applied to thevertical drive lever 85 a is converted to the drive force in thevertical direction by the conversion mechanism, which includes the firstthin portion 90 a and the first flexure neck portion 89 a. The verticalmovement outside the flexure body 84 vertically moves the opticalelement 38. When the optical element 38 is housed in the lens frame 40,therefore, the conversion mechanism is particularly effective.

[0200] (8) The flexure fixing portion 91, the connection block 84 a, andthe restriction links 93, 94 are formed by a single member. Therestriction links 93, 94 are coupled to the flexure fixing portion 91and the connection block 84 a by the neck portions. This forms the linkmechanism with a simple structure without increasing the number ofcomponents.

[0201] (9) The first thin portion 90 a and the first flexure neckportion 89 a are arranged on the same horizontal plane. When a driveforce is applied to the vertical drive lever 85 a, this arrangementprevents the rotational moment from being produced at the first flexureneck portion 89 a so that the vertical drive force is accuratelyconverted to the vertical drive force of the optical element 38.

[0202] (10) The second thin portion 90 b and the second flexure neckportion 89 b are arranged on the same vertical plane. When a drive forceis applied to the horizontal drive lever 85 b, this arrangement preventsthe rotational moment from being produced at the second flexure neckportion 89 b so that the vertical drive force is accurately converted tothe horizontal drive force of the optical element 38.

[0203] (11) Since a movement amount that is less than the movementamount at the tip ends of the drive levers 85 a, 85 b is transmitted tothe link mechanism of the flexure body 84, fine movement of the opticalelement 38 is possible. In accordance with the reduction in the movementamount, the movement amount of the optical element 38 is accuratelycontrolled.

[0204] (12) The movement amounts of the drive levers 85 a, 85 b areadjusted by the adjusting washers 99 and the adjusting buttons 100.Therefore, the movement amounts of the drive levers 85 a and 85 b do notchange, and the position of the optical element 38 is accuratelycontrolled.

[0205] (13) The adjusting washers 99 and the adjusting buttons 100 arearranged between the drive levers 85 a, 85 b and the frame 142. Thedistance between the drive levers 85 a, 85 b and the frame 142 (i.e.,the movement amounts of the drive levers 85 a, 85 b) are adjusted by thequantity of the adjusting washers 99 and adjusting buttons 100. Thisaccurately controls the position of the optical element 38 with a simplestructure.

[0206] (14) The optical element 38 is moved in its tangential directionby operating the horizontal drive lever 85 b, and the optical element 38is moved in the optical axis direction by operating the vertical drivelever 85 a. Operating the two drive levers 85 a, 85 b thus easily andaccurately controls the posture of the optical element 38.

[0207] (15) The flexure bodies 84 are arranged between adjacent bearingsurface blocks 50 a. This arrangement makes the optical element holdingapparatus 139 compact.

[0208] (16) The rotational pivots that connect the restriction links 93,94 are the flexure neck portions 89 a-89 d that have relatively smallcross-sectional areas. This structure forms the flexure fixing portion91, the connection block 84 a, and the restriction links 93, 94 with anintegral member by a simple structure.

[0209] (17) The drive levers 85 a, 85 b are urged toward the frame 142by the return springs 103. Contact of the drive levers 85 a, 85 b withthe adjusting buttons 100, which result from the urging forces of thereturn springs 103, determines the positions of the drive levers 85 a,85 b. That is, the positions of the drive levers 85 a and 85 b aredetermined by the thickness of the adjusting washers 99 and theadjusting buttons 100. The adjusting washers 99 and the adjustingbuttons 100 enable the positions of the drive levers 85 a, 85 b to beset more accurately compared to when the positions of the drive leversare determined by the meshed amount of screws.

[0210] (18) The flexure housing recesses 81, which house the flexurebodies 84 of another optical element holding apparatus 139, are providedbetween the adjoining flexure bodies 84. This structure makes thesuperimposed optical element holding apparatuses 139 smaller.

[0211] (19) The flexure housing recesses 81 are arranged at positionsshifted by 180° with respect to the associated flexure bodies 84. Thus,by superimposing multiple optical element holding apparatuses 139 in astate shifted from one another by 180°, the superimposed optical elementholding apparatuses 139 become compact.

[0212] (20) The connection surface 40 a, which is connected to the frame142 of another optical element holding apparatus 139, is defined on theend face of the frame 142. The arrangement of the space adjusting spacerbetween the connection surfaces 40 a enables the adjustment of thepositions of the optical element holding apparatuses 139 relative toeach other. That is, the space adjusting spacer enables rough adjustmentof the positions of the optical element held by the optical elementholding apparatuses 139. Afterward, the drive levers 85 a, 85 b of theoptical element holding apparatuses 139 are driven and the thickness ofthe adjusting washers and the adjusting buttons is changed to move theoptical element to a target position. The space adjusting spacer may beannular so that its shape is generally the same as the connectionsurfaces. The spacer may also be divided into a number of portions(e.g., washers) to be arranged at a plurality of locations on theconnection surfaces.

[0213] (21) In each lens barrel module 420, a plurality of opticalelements 38 are held by the optical element holding apparatuses 139. Theoptical elements 38 in each lens barrel module 420 are accuratelypositioned, thus improving the imaging performance of the entire lensbarrel 37.

[0214] (22) The exposure apparatus 31 performs exposure using theprojection optical system 35 that includes the lens barrel 37, in whichthe optical element 38 is held by the optical element holding apparatus139. This improves the imaging performance of the projection opticalsystem 35 and improves the exposure accuracy.

[0215] (23) In the exposure apparatus 31, the drive levers 85 a, 85 b,which drive the flexure member 41, is arranged between the lens frame40, which supports the optical element 38, and the frame 142. Thus, theactuation of the drive levers 85 a, 85 b enables the movement of theoptical element 38 with the six degrees of freedom of motion.Accordingly, the frame 142 and the lens frame 40 do not have to bemachined accurately, and the positioning of the optical element 38 isperformed easily and accurately.

[0216] (24) In the exposure apparatus 31, the three flexure members 41each have the first restriction block 93 a and the second restrictionblock 94 a, which are rigid bodies having a predetermined length. Thelens frame 40 is supported on the frame 142 by six rigid bodies intotal. In addition, each rigid body has the six degrees of freedom ofmotion. This enables precession relative to the frame 142. Thus, theoptical element supported by the lens frame 40 may be supported in akinematical manner in a three-coordinate axis system R-θ-Z, the centerof which is the origin, the radial direction of which is R, thecircumferential direction of which is θ, and the optical axis directionof which is Z.

[0217] (25) In the exposure apparatus 31, the flexure member 41 has theposition adjusting mechanism 108, which adjusts the distance between thelens frame 40 and the frame 142. The adjustment of the distance betweenthe lens frame 40 and the frame 142 enlarges the movement range of theoptical element 38. The usage of this to correct the residual aberrationsignificantly improves the imaging performance of the projection opticalsystem 35 and improves the exposure accuracy of the exposure apparatus31.

[0218] (26) In the exposure apparatus 31, the drive levers 85 a, 85 b,which are attached to the drive levers 85 a, 85 b of the flexure body 84of the three flexure members 41, are displaced to displace the flexurebody 84. The displacement of the flexure body 84 positions the opticalelement 38. By using the flexure members 41 to move the optical element38, unpredicted distortion is prevented from occurring in the opticalelement 38. Accordingly, the optical element 38 may accurately be movedwhile maintaining the accuracy of the optical element 38.

[0219] (27) When a certain object is held on a predetermined fixedportion by six rigid bodies in a kinematical manner, a kinematicalunique point is produced when three or more extension lines of the sixrigid bodies intersect at the same point. The object is held in anunstable manner at the unique point causing accurate positioning of theobject to be difficult. In comparison, in the exposure apparatus 31,presuming that six lines connect the flexure neck portions 89 a-89 d atthe two ends of each restriction block 93 a, 94 a, which define therigid body of each flexure member 41, three or more lines do notintersect at the same point. Thus, the positioning of the opticalelement 38 is performed without producing a kinematical unique point.

[0220] (Fourth Embodiment)

[0221] An optical element holding apparatus according to a fourthembodiment of the present invention will now be discussed with referenceto FIGS. 40-42 centering on parts differing from the first embodiment.

[0222]FIG. 40 is a perspective view schematically showing an opticalelement holding apparatus 121 of the fourth embodiment. As shown in FIG.40, in the optical element holding apparatus 121, a lens frame 122,which holds an optical element 38, is held on a frame 124 by sixindependent (five shown in the drawing) rigid bodies 123.

[0223]FIG. 41 is a cross-sectional view of the rigid body 123, FIG. 42is a cross-sectional view taken along line 42-42 in FIG. 21. As shown inFIGS. 41 and 43, the rigid body 123 is formed by a metal square pillar,and notched rotational pivots 125, the structure of which is the similarto the flexure neck portions 89 a-89 d of the third embodiment, areformed near the ends of the rigid body 123. One end of each rigid body123 is directly fixed to the frame 124 and the other end is fixed to theframe body 122 by an attaching member 126. When presuming there are sixlines connecting the rotational pivots 125 at the ends of each rigidbody 123, the six rigid bodies 123 are also arranged so that three ormore lines do not intersect at the same point.

[0224] In addition to advantages (1), (5), (8), (22), (24, and (27), thefourth embodiment having the above structure has the followingadvantages.

[0225] (Fifth Embodiment)

[0226] An optical element holding device according to a fifth embodimentof the present invention will now be discussed centering on partsdiffering from each of the above embodiments. As schematically shown inFIG. 43, in an optical element holding apparatus 131 of the fifthembodiment, the lens frame 122 of the optical element holding apparatus121 of the fourth embodiment is eliminated. A bearing surface blockmechanism or a clamp member is attached to one of the ends of the rigidbody 123 to directly clamp the optical element 38.

[0227] This also obtains the same advantages as the optical elementholding apparatus 121 of the fourth embodiment.

[0228] (Sixth Embodiment)

[0229] An optical element holding apparatus according to a sixthembodiment of the present invention will now be discussed centering onparts differing from each of the above embodiments.

[0230]FIG. 44 is a perspective view schematically showing an opticalelement holding apparatus 136 of the sixth embodiment. As shown in FIG.44, in the optical element holding apparatus 136, the position adjustingmechanism 108 of the optical element holding apparatus 139 of the thirdembodiment is eliminated. More specifically, in the optical elementholding apparatus 139 of the third embodiment, in the optical elementholding apparatus 139 of the third embodiment, the vertical drive lever85 a, the horizontal drive lever 85 b, the adjusting washers 99 and theadjusting buttons 100, which adjust the displacement of the two drivelevers 85 a, 85 b, and their peripheral structure are eliminated.

[0231] In such structure, when the optical element 38 is placed on thelens frame 40, the flexure member 41 functions to obtain the six degreesof freedom of motion, which include the three movements along the polarcoordinate system R-θ-Z and rotations about the three coordinate axes R,θ, Z. Accordingly, the optical element 38 is held on the frame 142 in akinematical manner. Further, although the range of position adjustmentof the optical element 38 is narrowed, the same advantages as theoptical element holding apparatus 139 of the third embodiment isobtained.

[0232] (Seventh Embodiment)

[0233] An optical element holding apparatus according to a seventhembodiment of the present invention will now be discussed centering onthe parts differing from the above embodiments.

[0234]FIG. 45 is a perspective view schematically showing an opticalelement holding apparatus 141 of the seventh embodiment 141. As shown inFIG. 45, the optical element holding apparatus 141 differs from theoptical element holding apparatus 121 of the fourth embodiment in thatthe shape of a rigid body 146 is changed and a length adjustingmechanism 143, which functions as a distance adjusting mechanism, isarranged at the middle of each rigid body 146. Further, rotationalpivots 144 located on the ends of two rigid bodies 146 are arranged inthe vicinity of each other so that two rigid bodies 146 share the samerotational pivot.

[0235]FIG. 46 is a cross-sectional view of one of the rigid bodies 146.FIG. 47 is a cross-sectional view taken along line 27-27 in FIG. 46.Referring to FIGS. 46 and 47, the rigid body 146 is made of a metalcylinder, and rotational pivots 144, which is formed by an annulargroove having a generally U-shaped cross-section, are formed near thetwo ends of the rigid body 146. The rotational pivot 144 functions inthe same manner as the flexure neck portions 89 a-89 d of the thirdembodiment. The rotational pivot 144 of another rigid body 146 isconnected to the vicinity of the rotational pivot. One end of each rigidbody 146 is directly fixed to the frame 124, which serves as a fixedportion, and the other end is fixed to the lens frame 122 by anattaching member 126.

[0236] The length adjusting mechanism 143, which is, for example, apiezo-element, is connected to a main control apparatus, which serves asa control apparatus fro controlling the operation of the entire exposureapparatus 31. The main control apparatus 145 detects the aberrationinformation of the projection optical system 35 based on the image ofthe pattern on the reticle Rt formed on an image surface of theprojection optical system 35 of the exposure apparatus. Further, themain control apparatus 145 receives information of the expanded lengthof the length adjusting mechanism 143 from the length adjustingmechanism 143 and obtains the distance between the lens frame 122 andthe frame 124 from the expanded length information. This adjusts thedistance between the lens frame 122 and the frame 124 and corrects theaberration of the projection optical system 35.

[0237] In addition to advantages (1) , (5) , (8) , (22) , (24, and (27),the fourth embodiment having the above structure has the followingadvantages.

[0238] (28) In the optical element holding apparatus 141, the maincontrol apparatus 145 detects the distance between the lens frame 122and the frame 124. The main control apparatus 145 controls the lengthadjusting mechanism 143 to adjust the distance between the lens frame122 and the frame 124 based on the detection result and the aberrationinformation included in the image of the pattern formed on the imagesurface side of the projection optical system 35.

[0239] Thus, the residue aberration in the projection optical system 35is accurately corrected. This further improves the exposure accuracy. Inaddition, since a piezo-element is employed as the length adjustingmechanism 143, the distance between the lens frame 122 and the frame 124is electrically adjusted in real time, and the aberration of theprojection optical system 35 is corrected by having the aberrationfollow changes in the state of the projection optical system 35.

[0240] (29) In the optical element holding apparatus 141, the distancebetween the lens frame 122 and the frame 124 is adjusted by adjustingthe length of the rigid bodies 146, which connect the lens frame 122 andthe frame 124, with the length adjusting mechanism 143. Thus, thedistance between the lens frame 122 and the frame 124 is adjusted with asimple structure and the range of the vertical movement and tiltingmovement of the optical element is enlarged.

[0241] It should be apparent to those skilled in the art that thepresent invention may be embodied in many other specific forms withoutdeparting from the spirit or scope of the invention. Particularly, itshould be understood that the present invention may be embodied in thefollowing forms.

[0242] In the third embodiment, the amounts of movement of the drivelevers 85 a and 85 b may be set by using, for example, piezo-actuatorsin place of the adjusting washers 99 and adjusting buttons 100. Theposture of the optical element 38,may be controlled in real time byusing a sensor, which detects the position of the lens frame 40.

[0243] In the third embodiment, the optical element 38 may be held bythe lens frame 40 without using the holders 43.

[0244] The optical element 38 may be a plane parallel plate, a mirror,or a half mirror instead of a lens. Further, a polarizing member, whichpolarizes exposure light, or a reflection optical member having areflection surface, which reflects exposure light, may be used as well.

[0245] The present invention may be adapted to an optical elementholding apparatus in the illumination optical system 33 of the exposureapparatus 31 or to an optical element holding apparatus, which holds anoptical element upright. Further, the invention may be adapted to anoptical element holding apparatus in an optical system of an opticalmachine, such as a microscope or an interferometer.

[0246] The present invention may be adapted to the optical system of acontact exposure apparatus, which exposes the pattern of a mask byhaving a mask and a substrate come into close contact, or a proximityexposure apparatus, which exposes the pattern of a mask by having a maskand a substrate arranged in the proximity of each other. The projectionoptical system is not limited to a full refraction type but may be areflection refraction type as well.

[0247] The present invention may be adapted to an exposure apparatus ofan equal magnification type or an exposure apparatus of an enlargementtype as well as a reduction exposure type exposure apparatus.

[0248] The present invention may also be adapted to an exposure systemthat transfers a circuit pattern onto a glass substrate or a siliconwafer from a mother reticle in order to produce a reticle or mask, whichis used in a light exposure apparatus, an EUV exposure apparatus, anX-ray exposure apparatus, or an electron-beam exposure apparatus. Theexposure apparatuses that use deep ultraviolet rays (DUV) or vacuumultraviolet rays (VUV) usually use a transmission reticle substrate.Quartz glass, fluorine-doped quartz glass, fluorite, magnesium fluoride,or crystal or the like are used as the reticle substrate. A proximitytype X-ray exposure apparatus and electron-beam exposure apparatus use atransmission mask substrate (stencil mask or membrane mask). A siliconwafer is used as the mask substrate.

[0249] The present invention may be adapted not only to an exposureapparatus, which is used to fabricate semiconductor devices, but also toan exposure apparatus, which is used to manufacture displays including aliquid crystal display (LCD) and transfers a device pattern onto a glassplate. The invention may also be adapted to an exposure apparatus, whichis used to produce thin-film magnetic heads and which transfers a devicepattern onto a ceramic wafer, and an exposure apparatus which is used tofabricate imaging devices, such as CCDs.

[0250] The present invention may be adapted to a scanning stepper, whichtransfers the pattern of a mask on a substrate with the mask andsubstrate being moved relatively and moves the substrate step by step.The present invention may also be adapted to a step and repeat typestepper, which transfers the pattern of a mask on a substrate withoutmoving the mask and substrate and which moves the substrate step bystep.

[0251] The exposure apparatus may use a light source, such as g rays(436 nm), i rays (365 nm), a KrF excimer laser (248 nm), F₂ laser (157nm), Kr₂ laser (146 nm) , and Ar₂ laser (126 nm) Further, harmonicwaves, which are obtained by amplifying the single-wavelength laser beamof the ultraviolet range or visible range emitted from a DFBsemiconductor laser or a fiber laser using an erbium-doped (orerbium-yttrium-doped) fiber amplifier and converting the amplified laserbeam to violet rays using a non-linear optical crystal.

[0252] The exposure apparatus 31 may be manufactured as follows.

[0253] First, at least some optical elements 38, such as a plurality oflenses or mirrors forming the illumination optical system 33 and theprojection optical system 35, are held by the optical element holdingapparatuses 39, 139, the illumination optical system 33 and theprojection optical system 35 are incorporated in the body of theexposure apparatus 31, and optical adjustment is performed. Then, thewafer stage 36 that includes multiple mechanical components (includingthe reticle stage 34 when using a scan type exposure apparatus) areattached to the body of the exposure apparatus 31 and wires areconnected. Then, a gas supplying pipe for supplying gas into the opticalpath of the exposure light EL is connected and the total adjustment(electric adjustment, operational check or the like) is performed.

[0254] The individual components of the optical element holdingapparatus 39 are assembled after impurities, such as machining oil ormetal substances, are cleaned off through ultrasonic cleaning or thelike. It is desirable that the exposure apparatus 31 should bemanufactured in a clean room where the temperature, humidity andatmospheric pressure are controlled and the degree of cleanness isadjusted.

[0255] The glass material in the embodiments is not limited to fluoriteand quartz glass, but may be a crystal, such as lithium fluoride,magnesium fluoride, strontium fluoride,lithium-calcium-aluminum-fluoride orlithium-strontium-aluminum-fluoride; fluoride glass ofzirconium-barium-lantern-aluminum; and modified quartz, such asfluorine-doped quartz glass, fluorine-hydrogen-doped quartz glass,quartz glass containing an OH group or quartz glass containing fluorineand an OH group.

[0256] A description will now be given of a method of fabricating adevice through a lithography process using the exposure apparatus 31.

[0257]FIG. 48 is a flowchart illustrating a process of fabricating adevice (a semiconductor device, such as IC or LSI, a liquid crystaldisplay, an image pickup device (CCD), a thin-film magnetic head ,and amicro machine). As shown in FIG. 48, first, the design (e.g., circuitdesign of a semiconductor device) of the functions and performance of adevice (micro device) is performed and the pattern design thataccomplishes the functions is carried out in step S151 (design step). Inthe next step S152 (mask producing step), a mask (reticle R or the like)on which the designed circuit pattern is formed is produced. In stepS153 (substrate producing step), a substrate (wafer W when a siliconmaterial is used) is produced using a material, such as silicon or glassplate.

[0258] In the next step S154 (substrate processing step), a circuit isformed on the substrate through the lithography technology using themask and substrate prepared in steps S151 to S153. Then, a device isassembled in step S155 (device assembling step) using the substrateprocessed in step S154. In step S155, steps, such as a dicing step, abonding step, and a packaging step (chip packaging or the like), areexecuted as needed.

[0259] Finally, inspection of the device manufactured in step S155, suchas an operational test and durability test, is performed in step S156(inspection step). Through the above steps, the device is completed.

[0260]FIG. 49 is a detailed flowchart of step S154 of FIG. 48 in thefabrication of a semiconductor device. In FIG. 40, the surface of thewafer W is oxidized in step S161 (oxidizing step). In step S162 (CVDstep), an insulating film is formed on the surface of the wafer W. Instep S163 (electrode forming step), electrodes are formed on the wafer Wby vapor deposition. In step S164 (ion implanting step), ions areimplanted in the wafer W. Steps S161 to S164 are a pre-process of theindividual stages of the wafer process and are selectively executed inaccordance with the required process at each stage.

[0261] When the pre-process is finished at each stage of the waferprocess, a post-process is executed as follows. In the post-process,first, a photosensitive agent is applied to the wafer W in step S165(resist forming step). Subsequently, the circuit pattern of a mask(reticle R) is transferred onto the wafer W by a lithography system(exposure apparatus 31) in step S166 (exposure step). Next, the exposedwafer W is developed in step S167 (developing step), and an exposedmember at a portion excluding the resist-remaining portion is removedthrough etching in step S168 (etching step). In step S169 (resistremoving step), unnecessary resist is removed. The pre-process andpost-process are repeated to form multiple circuit patterns on the waferW.

[0262] In the device fabrication method, the exposure apparatus 31 isused in the exposure step (step S166) so that the degree of theresolution by the exposure light EL of the ultraviolet range isimproved. Further, the exposure control is executed with high accuracy.This ensures production of high-integration devices with the minimumline width of about 0.1 μm and increases the yield.

1. An optical element holding apparatus (39) provided with a holdingportion (43) for holding a peripheral portion of an optical element,characterized in that the holding portion includes: a bearing surfaceblock (50 a, 73) having a bearing surface (49, 92), which contacts theperipheral portion of the optical element; and a bearing surface blocksupport mechanism (51) for rotatably supporting the bearing surfaceblock about a tangential axis (Y) of the optical element.
 2. The opticalelement holding apparatus according to claim 1, characterized in thatthe bearing surface block support mechanism rotatably supports thebearing surface block about a radial axis (X) of the optical element. 3.The optical element holding apparatus according to claim 2,characterized in that the bearing surface block support mechanismmovably supports the bearing surface block in a radial direction of theoptical element.
 4. An optical element holding apparatus characterizedby: a holding portion (43) for holding a peripheral portion of anoptical element; and a fastening portion (42) to which the holdingportion is fastened; wherein the holding portion includes: a bearingsurface block (50 a, 73) having a bearing surface (49, 92) that contactsthe peripheral portion of the optical element; a base portion (56) fixedto the fastening portion; and a pair of link mechanisms (57, 58) forrestricting movements of the bearing surface block relative to the baseportion in a plurality of different directions and for connecting thebase portion and the bearing surface block rotatably about each axis ofthe plurality of different directions.
 5. The optical element holdingapparatus according to claim 4, characterized in that the pair of linkmechanisms include: a tangential restriction link (57) for restrictingmovement of the bearing surface block related with a tangentialdirection of the optical element and for connecting the bearing surfaceblock rotatably about a tangential axis (Y); and an optical axisdirection restriction link (58) for restricting movement of the bearingsurface block related with an optical direction of the optical elementand for connecting the bearing surface block rotatably about an axis (Z)in the direction of the optical axis.
 6. The optical element holdingapparatus according to claim 4 or 5, characterized in that the holdingportion includes rotational pivots (55 a, 55 b, 55 c, 55 d) connectingthe base portion, the bearing surface block, and the pair of linkmechanisms to one another.
 7. The optical element holding apparatusaccording to claim 6, characterized in that the rotational pivots arearranged along or in the vicinity of a line that is parallel to a normalline perpendicular to the bearing surface and extends through a middleposition of the bearing surface.
 8. The optical element holdingapparatus according to claim 6 or 7, characterized in that the bearingsurface block is formed integral with the pair of link mechanisms, therotational pivots and the fixed portion.
 9. The optical element holdingapparatus according to any one of claims 1 to 8, characterized in thatthe bearing surface block has a plurality of bearing surfaces (39)formed to have a predetermined length in a tangential direction of theoptical element and arranged at predetermined intervals.
 10. The opticalelement holding apparatus according to any one of claims 1 to 8,characterized in that the bearing surface block has a bearing surface(92) formed to have a predetermined length in a tangential direction ofthe optical element and having approximately the same length as alongitudinal length of the bearing surface block.
 11. The opticalelement holding apparatus according to any one of claims 1 to 10,characterized in that the bearing surface has undergone a process ofincreasing a coefficient of friction with respect to the opticalelement.
 12. A lens barrel (37) for accommodating a plurality of opticalelements (38), characterized in that an optical element holdingapparatus (39) according to any one of claims 1 to 11 is provided forholding at least one of the plurality of optical elements.
 13. A lensbarrel (37) having at least one lens barrel module (420) foraccommodating one or more optical elements (38), characterized in that:the at least one lens barrel module is provided with an optical elementholding apparatus (39) according to any one of claims 1 to 11 forholding at least one of the plurality of optical elements.
 14. Anexposure apparatus (31) for transferring an image of a pattern formed ona mask (R) onto a substrate (W) through a projection optical system(35), the exposure apparatus being characterized in that: the projectionoptical system has a lens barrel (37) which accommodates a plurality ofoptical elements (38); and the lens barrel is provided with an opticalelement holding apparatus (39) according to any one of claims 1 to 11for holding at least one of the plurality of optical elements.
 15. Aholding apparatus characterized by: a holding portion (42) for holding amember to be held (38), wherein the holding portion includes a drivemechanism (85 a, 85 b, 108, 143) for providing the member to be heldwith three movements along three coordinate axes (R, θ, Z) with anorigin being substantially the center of the member to be held and tworotations about at least two coordinate axes of the three coordinateaxes.
 16. The holding apparatus according to claim 15, characterized inthat: the holding portion includes a support member for supporting themember to be held and a fastening portion (142, 124) to which theholding portion is fastened; wherein the drive mechanism is arrangedbetween the support member and the fastened portion.
 17. The holdingapparatus according to claim 16, characterized in that the drivemechanism has six rigid bodies (93 a, 94 a, 106 a, 106 b, 123, 142)having a predetermined length.
 18. The holding apparatus according toclaim 17, characterized by a distance adjusting mechanism (108, 143) foradjusting the distance between the support member and a fastenedportion.
 19. The holding apparatus according to claim 18, characterizedin that the distance adjusting mechanism includes a length adjustingmechanism (143) which adjusts the length of a certain rigid body of thesix rigid bodies.
 20. The holding apparatus according to claim 15,characterized in that the drive mechanism includes a plurality offlexure members (41) connected to the member to be held, and adisplacement member (99, 100) connected to at least one of the pluralityof flexure members which displace the flexure members to provide themember to be held with the three movements and the two rotations. 21.The holding apparatus according to claim 20, characterized in that theflexure members include three flexure members arranged at equalintervals around the member to be held.
 22. The holding apparatusaccording to claim 20 or 21, characterized in that the at least oneflexure member includes: a base portion (91) fixed to the connectingportion; a connection block (84 a) connected to the member to be held;and a pair of link mechanisms (93, 94) for restricting movements of thefastened portion and the connection block in a plurality of differentdirections and for rotatably supporting the fastened portion and theconnection block about axes of the plurality of different directions.23. The holding apparatus according to claim 22, characterized in thatthe pair of link mechanisms includes: a horizontal restriction link (94)for restricting movements of the base portion and the connection blockin a horizontal direction and for rotatably connecting the base portionand the connection block about an axis (Y) in the horizontal direction;and an intersecting direction restriction link (93) for restrictingmovements of the fastened portion and the connection block in adirection intersecting the horizontal direction of the fastened portionand the connection block and for rotatably connecting the fastenedportion and the connection block about an axis (Z) in the intersectingdirection.
 24. The holding apparatus according to claim 22 or 23,characterized in that the at least one flexure member includesrotational pivots (89 a, 89 b, 89 c, 89 d) which connects the fastenedportion, the connection block, and the pair of link mechanisms.
 25. Theholding apparatus according to claim 23 or 24, characterized in that theat least one flexure member includes a conversion mechanism (90 a, 90 b)which converts drive force applied to the displacement member in apredetermined direction to drive force in a direction differing from thepredetermined direction.
 26. The holding apparatus according to claim25, characterized in that the conversion mechanism converts drive force,which is applied to the displacement member in a direction perpendicularto the member to be held, to a drive force, which is horizontal to themember to be held.
 27. The holding apparatus according to claim 25,characterized in that the at least one flexure member converts driveforce, which is applied to the displacement member in a firstperpendicular direction with respect to the member to be held, to asecond perpendicular direction, which differs from the firstperpendicular direction, with respect to the member to be held.
 28. Theholding apparatus according to any one of claims 23 to 27, characterizedin that the base portion, the connection block, and the pair of linkmechanisms are formed from a single member, and the at least one flexuremember includes a plurality of link notch springs (89 a, 89 b, 89 c, 89d), formed from the single member to link the base portion, theconnection block, the horizontal restriction and vertical restrictionlink.
 29. The holding apparatus according to claim 28, characterized inthat: the conversion mechanism includes a plurality of conversion notchsprings (90 a, 90 b) formed on the base portion; and the plurality oflink notch springs include a first link notch spring (89 a) connected tothe intersecting direction restriction link (93), the plurality ofconversion notch springs include a first conversion notch spring (90 a)used to convert drive force, which is applied to the drive mechanism ina first perpendicular direction with respect to the member to be held,to a second perpendicular direction, which differs from the firstperpendicular direction with respect to the member to be held, and thefirst link notch spring and the first conversion notch spring arearranged on the same plane that is horizontal to the member to be held.30. The holding apparatus according to claim 29, characterized in thatthe plurality of link notch springs include a second link notch spring(89 d) which connects the connection block to the intersecting directionrestriction link (93), wherein the first and second link notch springsare arranged on the same plane that is perpendicular to the member to beheld.
 31. The holding apparatus according to any one of claims 22 to 30,characterized by a transmission portion (85 a, 85 b) connected to thepair of link mechanisms to transmit drive force to the pair of linkmechanisms.
 32. The holding apparatus according to claim 31,characterized in that the application of drive force moves thetransmission portion and the pair of link mechanisms, and thetransmission portion is elongated so that a movement amount of the pairof link mechanisms is smaller than a movement amount of the transmissionportion.
 33. The holding apparatus according to claim 32, characterizedby a moving amount determining member (99, 100) for determining themovement amount of the transmission portion.
 34. The holding apparatusaccording to claim 28, characterized in that the holding apparatus isarranged on a support member (142) which supports the holding apparatus,and the moving amount determining member is arranged facing thetransmission portion on the support member (142).
 35. An optical elementholding apparatus characterized by: a holding member (40) for holding aperipheral portion of an optical element (38); three flexure members(41) for holding the holding member at three locations; and first andsecond manipulation members (85 a, 85 b), connected to at least one ofthe flexure members to manipulate the at least one flexure member,wherein the manipulation member is held such that manipulation of thefirst manipulation member causes the at least one flexure member to movethe optical element in a first direction and such that manipulation ofthe second manipulation member causes the at least one flexure member tomove the optical element in a second direction that differs from thefirst direction.
 36. The optical element holding apparatus according toclaim 35, characterized in that the first direction is a tangentialdirection of the optical element, and the second direction is an opticalaxis direction of the optical element.
 37. An optical element holdingapparatus (139) characterized by: a holding member (40) including aholding portion (43) for holding a peripheral portion of an opticalelement (38); and a holding apparatus according to any one of claims 15to 34 for holding the holding member.
 38. The optical element holdingapparatus according to any one of claims 35 to 37, characterized in thatthe holding portion (43) has a plurality of bearing surface blocks (50a) each having a bearing surface (49), which contacts the peripheralportion of the optical element, and each of the flexure members isarranged between adjoining bearing surface blocks.
 39. A lens barrel(37) having at least one lens barrel module (420) for accommodating oneor more optical elements (38), the lens barrel being characterized inthat: the at least one lens barrel module is provided with an opticalelement holding apparatus (139) according to any one of claims 35 to 38which holds the one or more optical elements.
 40. An exposure apparatus(31) for transferring an image of a pattern formed on a mask (R) onto asubstrate (W) through a projection optical system (35), the exposureapparatus being characterized in that the projection optical system hasa lens barrel (37) which accommodates a plurality of optical elements(38); and the lens barrel (37) is provided with an optical elementholding apparatus (139) according to any one of claims 35 to 38 to holdat least one of the plurality of optical elements.
 41. The exposureapparatus according to claim 40, characterized in that the opticalelement holding apparatus includes a control mechanism (145) whichcontrols the drive mechanism to detect the distance between the holdingportion and the fastening portion and to adjust the distance between theholding portion and the fastening portion based on the detection resultand aberration information included in an image of the pattern formed onan image surface side of the projection optical system.